This is what I see in game:

45.32% mastery
7.69% crit
21501 spellpower

SS-flashheal : 83816
normal flash heal: 51350

SS boost factor: 1.595583476109

With 19546 spellpower

SS-flashheal : 78678
normal flash heal: 49140

SS boost factor: 1.601098901099

Spirit shell formula: (1+mastery)*(1+crit)*(1+0.3*crit) --> (1+0.4532)*(1+0.0769)*(1+0.3*0.0769) = 1.601054501416

Seems like the differences are really down to rounding up approximations in the reported heal value of the spell in the tooltip.

I used a crit potion to add 990 crit which took my crit to 9.34%.

With 19546 spellpower ss-flashheal: 80270

SS boost factor: 1.633496133496

Spirit shell formula: (1+0.4532)*(1+0.0934)*(1+0.3*0.0934) = (1+0.4532)*(1+0.0934)*(1+0.3*0.0934) = 1.633450667218

Looks pretty exact to me.

But look at the 2nd set of values where I switched off inner fire:

49140*(1+0.4532)*(1+0.0769)*(1+0.3*0.0769) = 78 675.818

The actual value is 78678, so only 2.2 points difference

It is possible that inner fire is messing things up, we can check to see if that is the problem. However I personally think this is just due to approximation errors.

[edit]

I tried again after un-equipping my weapon to change the values somewhat:

Without inner fire

Sp: 12802
mastery: 43.88%
Crit: 7,62%

flash: 38066
ss-flash: 60289

38066*(1+0.4388)*(1+0.0762)*(1+0.3*0.0762) = 60 290.218

With inner fire

flash: 40168
ss-flash: 63619

40168*(1+0.4388)*(1+0.0761)*(1+0.3*0.0762) ~ 63 619

Spot on again.

So inner fire is not failing either. I think what happens is the tooltip is rounding up in every single value and small differences are magnified because you have everything multiplied together. To test my theory:
40467.5*(1+0.43876)*(1+0.07606)*(1+0.3*0.07616) ~ 64 083, which is a difference of 464 or 0.7293418633%.

The most likely explanation is that the tooltip value dispays have a error when rounding up or down and that is what causes the deviation at certain "unlucky" values of crit, mastery and average heal value. My guess is that the last digit is omitted instead of round up and down

Strange !
I cannot be connected actually but i have tested like you with several values of gear and found it as Havroc.
I will tested again (i have only tested on GH)
i think explanantion of havroc is good. We must use the value indicated on the tooltip and not with no rounding.

when modification has been applied on Aegis from 30% to 50%, i made the same comment about SS which is not following the modification.
I do not think it is a bug, it is a designer decision to create an exception.
This choice to avoid to apply the modification on SS was a good decision because SS would be too much powerfull.

We also all think, i supposed, that Aegis up from 30% to 50% is not a good change because disc is now too much strong compare to others healers.

In fact , this is the combinaison of both modifications which was not a good decision : improve power and mana regen beacuse we are now closed to be able to spam PoH with 50% aegis.

Dic gameplay is more and more spam PoH under SS and Spam PoH without SS, just refresh PWS for Rapture and stack up Archangel.

I have to agree, disc is ridculously overpowered if damage comes in huge predictable bursts... we tried 2nd boss in HoF on heroic yesterday, I was a bit late to the raid and the 3 other healers struggled. Then I swapped with the HPal and just dominated the meter and the unseen strikes were no problem... i mean with good timing I could place SS on both groups for 60% of my hp and a few DA after SS while the shells are still on the people until the strike comes, resulting in huge amounts of absorbs...

And timing rapture with a triple spirit procc (which puts me at 21k spirit) now results in 42k mana... thats a net plus of about 24k mana for 1 shield, if I can pop multiple during the proccs I gain more mana than with a fiend...

The combination of both those buffs was more than just a slight buff to a good disc priest who can time his stuff right :X I'm worried the nerfbat may be hitting us back and into a worse state than before the buffs >.<

Disc is not OP. Our max HPS is still not as good as other healers. We are now better at sticking up big absorption stacks and we don't have to rely exclusively on spirit shell for it.

Blade lord and maybe windlord, disc is OP, but for everything else it is in line with other healers.

Our mana balance is still not as good as other healers. Other classes can switch to int stacking at like 10-11k spirit. I think the multi proc rapture will be nerfed, but 200% rapture is here to stay.

I am getting like 600-700k mana back from rapture on windlord and bladelord.

Yes, i hope that next modification will not be simply to remove them....
Probably our main problem was the amount of mana consumption while using SS.
To reduce cost of spell under SS proc would be better.
Wait & see !

***************
Now, i answer to your post of friday , Havroc.

1/ We agree 600 mastery points are 2.5%

2/ OK, usualy i do not take this notation.(i took it to be more understandable)
Notation that i take is near from you but results are same at the end.

This notation comes from
Average Heal = base Heal + CoefSP * SP = Base Heal * ( 1 + 1%* SP* CoefSP/Base Heal)

becomes
Average Heal = Base Heal * ( 1 + 1%* SP / ScoreSP)
with ScoreSP = Base Heal/CoefSP = 19428/187.1%/100 ~ 103.838

Basicaly k universal constant that you use is not universal but only applied on PWS.
It is the same factor that i have defined in my formula :
k = 1%/ScoreSP = 0.0000963043....

You have found k=0.000096564716 which is probably not correct if Wowhead database is up to date.
But i found new evolution on WoWdb (Power Word: Shield - Baseline - Priest - Class Abilities - Spells - WowDB)
where PWS seems to have a different base value depending on Disc spec.

I have checked IG the correct value and i have confirmed that WoWHead was correct.
PWS = 61427 on tooltip and it is the value shown when casted with SP=12695 and mastery= 5342 points = 0.422583 (42.26% on tooltip)
Verification by formula gives the same result = PWS = 19428* ( 1 + 1%* 12695 / 103.838)*(1 + 42.2583%) = 61427.6 which matchs perfectly well.


Anyway to take k=0.000096564716 or 0.0000963043 will not have a real influence on the result.
And this is not on this value that we have discussed.


I come back on your formula because i think you made a mistake in buff behavior if "spellpower" = total fully buffed spellpower

You wrote
%increase_SP = 100*(Int*B*k)/(1+spellpower*k)

My formula is
%increase_SP = 100*(Int*B)/(100*ScoreSP+spellpower)

Which are exactly the same with k = 1%/ScoreSP
So on this point, we are ok together.

The problem for me is the definition of B
you miss the +10% of raid spell buff (given by sham/warlock/mage).
So you miss a 10% of improvement also done by the +100 INT

so in your example at 25000 spellpower 100 intellect adds
%increase_SP = 0.2826152081*B which is the same result as you if i take ScoreSP~100 as you have tacken k~0.0001.

for reference, you found 100*B*0.0001/(1+2.5)*100 = 0.2857142857*B%

except that B = 1.1*1.1*1.05*1.05 = 1.334025 (instead of yours 1.1*1.05*1.05 = 1.21275)


3.
with 2.5% for 600 points, you wrote :
OK you did not take the same amount of mastery at the beggining.
Let's go with my formula with your datas :

PWS = Base Heal * ( 1 + 1%* SP / ScoreSP)*(1 + %Mastery)


%increase_mast = 100*(2.5%*mastRat_added)/(ScoreM*(1 + %Mastery))
with ScoreM = 600.

so can also writen :
%increase_mast = 100*(mastRat_added)/(24000*(1 + %Mastery))

With +100 mastery added and 7000 mastery on gear (including the buff raid of 3000 mastery),
%mastery = 2.5%* (8 + 7000/600) = 49.1667%

So
%increase_mast = 0.2793296089
Whis is exactly the same result as you.


So we are agree together that for PWS :
- INT is stronger than MASTERY on Equipement (except gems).
- MASTERY is stronger than INT on gems because of the bonus 2:1

We are also agreed that INT calculation does not take into account OverHeal estimation which reduce the power of INT compare to Mastery which will not create OverAbsorb if PWS is applied on tank for Rapture.
edit : i have canceled this remark because it is not applicable to PWS since INT is including in the absorb and there is no healing part which can Overheal.

So your long memo to explain me that i was wrong was not necessary because i have not not writen anything else for the PWS alone that you wrote.
I quote me :




4. Gameplay conclusion
Make the complete gameplay rotation, mastery is poor compare to others stats for PoH (and more poor for the others spells that you use inside the disc gameplay).
The up from 30% to 50% has improved the mastery behavior on PoH but it is still poor compare to INT and Critical stats. and is completely useless for all others spells.

I understand your comment about the effect of critical which is not completly used because of our overheal ratio on PoH.
We need to study both.
First without considering OH and adding in second step the effect of OH on the stats.

As we have different canonic formula but same result at the end, i am sure that you can see it in your simulation when you combine all together all the spell with actual gameplay of disc.


For example (and once again without introducing effect of overheal of stats)

PW:S 9%

PoH 15%

Atonnement 6%

Aegis 30%

SS PoH 30%

Others 10%

Which is a tipical gameplay absorb oriented (84% PWS / POH)

I find the following result :

For +100 of a given stat

SP INT CRIT MAST HASTE

0,352% 0,435% 0,180% 0,161% 0,224%

Which lead me to the conclusion that INT is "always" better than Mastery even on gems.
("always" has to be ponderate with OverHeal done with INT / CRIT on PoH/atonnement and the others spells)

on this example, Mastery is better than Critical because Critical will create more OverHeal than mastery will do.(difference is mainly on the healing part of spells like PoH or "others spells" category)

Haste is a very good stat as usual but is limited to burst mode. If we consider that burst mode is most important behavior of the disc gameplay , then haste is very strong but i hesitate since there is a relationship between Haste and Spirit.


**************
To conclude, i would be enjoyed to continue this discussion, but first agree on point 1, 2 and 3 because we are in line together.
then , we can go more deeply in point 4.


NO !
We have shown this value for PWS and PoH done under SS, not for PoH spell !
For PoH without SS activation, it is arround 0.0012% per stat point at 50% mastery. (it was at 0.008% before the change on Aegis)

As you said, blade lord and windlord, disc is really OP. You can completely trivialize 2 of the main mechanics of these fights.
On Grand Empress I also found disc to be really good, the absorbs work wonders for the dissonance fields in P1 and every last bit of DA is used up in P3 so you don't have to worry about rolling it.

I'm simply worried that the eventual nerfs may be too harsh, since disc will now always be pretty much overpowered compared to other healers when there are large predictable bursts of damage. On other fights, disc does not seem all that good, but hey that's what holy's for

Also may I ask how much spirit you guys are currently using and feeling comfortable with?
I think I will stick with my ~8.5k spirit for now, since I can keep some mana until the end of the fights with both disc and holy, but I have 3 spirit proccs, so that may somewhat screw my feelings towards less static spirit and more int/mastery...

Oh yeah, forgot to mention the flask and food but I never looked back at the spirit versions after Hamlet made his blog entry about it.

Hamza I am now at 13.5k fully buffed spirit and I have Darkmoon trinket and tailoring spirit proc. I am currently able to practically spam 9:2:1 PoH:PWS:Cascade, with a little PoM, renew and atonement (HF/penance/smite) thrown into the mix for a period of 8 minutes, if I use all my cooldowns correctly. I will now keep my spirit constant and stack mastery int all the way.



We agree on points 1, 2 and 3. If you look carefully you will see that I calculated B with inner will, not with inner fire. I left B as it is exactly because we have two stances. I did my actual calculations on the values using the value of B for inner fire.


But on 4 we disagree completely, because the values you quoted don't affect overheal. Mastery affects all absorbs in the same way. I dont understand how you find that it doesnt.

The aegis part of PoH is 0.5*base*(1+mastery)*(1+crit). Increaseing mastery by an amount dM leads to an improvement of dM/(1+mastery). Exactly as it does for PoH. I think you confused what I said. I am not saying that mastery improves PoH. I am only concerned about its effect on abosrbs, not on the overall healing of any spell.

The improvement in individual spells is of no interest to me, because it is a value that only has meaning for burst HPS. Overheal modifies the value of int and crit so strongly that it is essentially of little meaning when trying to see the overall effect.

Basically this is the theory. Let us say that your healing breakdown is a% absorbs and (100-a)% normal heals. We assume that we can ignore partial absorbs (this is not the case for a few encounters) so adding M mastery rating will increase the healing from absorbs by M/(28800+total_mastery_rating). We assume that adding I intellect will increase the power both absorbs and heals by I*B*k/(1+spellpower*k). However there is also the question of overheal. We will assume that all spells which overheal by any amount receive zero benefit from increased healing and all other spells receive full benefit (again not true, but a reasonable approximation).

Thus adding M mastery will improve overall healing by a%*M/(28800+total_mastery_rating).

Adding I intellect will improve overall healing by a%*I*B*k/(1+spellpower*k) + (1-a)%*I*B*k/(1+spellpower*k)*(1-OHR), where OHR is the overheal rate, i.e. the percentage of spells that overheal by any mount.

I determine OHR by sampling at random 30 spells from the log and checking how many of them overheal. I find that I have a very high overheal rate, especially on PoH. About 50% of my casts overheal by any amount.

Now if we take mastery and spellpower values, which we used before then intellect is better per point than mastery for absorbs by a factor that is equal to the buff constant B. i.e. we get M/(28800+total_mastery_rating) ~ I*k/(1+spellpower*k). Using inner fire B ~1.31. If we now look at gems where you have a 2:1 ratio, then what you get is that 2 mastery improves absorbs by roughly 50% more than 1 intellect. Thus in order for mastery in gems to be better than intellect we require that:

a%*0.5 > (1-a)%*(1-OHR).

For 60% absorbs that translates to

0.3 > 0.4*(1-OHR). In other words we need OHR to be just 25% in order for mastery on gems to be better than intellect. Usually even my total overheal is more than 25% and here we talking about overheal rate not overall overheal.

At 70% absorbs we get 0.35 > 0.3*(1-OHR). I.e. it is impossible to get a better deal from intellect on gems.

It is safe to say that unless mastery becomes ridiculously high (>60%) for anyone whose absorbs are more than 60% of total healing gemming mastery over intellect gives you a better overall deal.

I personally prefer stacking mastery and spirit, so I am able to spam PoH+PWS+Cascade+atonement without pause at all times. I can't say for sure that its the best strategy as I haven't been able to make into the top 10 in any fight so far, though I made it into the top 20 on several fights, but it is certainly a stategy that produces good results for me.

Right now I'm struggling with the difference of amount healed with PoH/DA when casting normal and under Spirit Shell.

The formula as can be found in this thread:

PoH(total) = base*(1+crit)(1.5+0.5mastery)
SSPoH = base(1+crit)(1+mastery)(1+0.3crit)

so
PoH(total)/SSPoH = 1.5 + 0.5mastery/(1+mastery)(1+0.3crit)

so with my usual 55% mastery and 25% crit on PoH (with inner Focus macroed to PoH) this should be

PoH(total)/SSPoH = 1.75/(1.55)(1.083) = 1.0425 which means that the average PoH including DA should be about 4.25% MORE heal than the Spirit Shell under the same conditions. I think at least one of the formulas must be wrong since this is not what can be seen in the logs.
What I usually see when comparing logs is that in fact both of them are quite close to each other but SS coming out ahead a moderate 5-10%.
Being so close together what is the main reason for everybody freaking out about spirit shell being OP when it actually just snipes heal from your healing fellows and provides a pre-stackable shield? I find it nice as a raid-Cooldown for single big bursts, but for actual hps its effect seems to be rather small.

If mastery <25%, then PoH(total)/PoH(SS) < 1 and SS will lower PoH hps.

If mastery >25%, SS will rise PoH hps. So stack mastery =)