Tested SS on PTR now. Mastery 49.5%, sp 12.2k, 16%crit
PoH w/o SS heal for 14.6k and make aegis for 6.5k. Its 17,7k average with 84% chance
Crit will heal for 30k and make aegis for 26k. Its 9k average with 16% chance.
Totally I expect to get 17.7+9=26.7k average. Thats a number I expect to get from SS.
But.
When I trigger SS up, my PoH make a 32.6k absorb. And I think formula here is different.

And for example, if target has 3grace stacks and Power Torrent proc, you can make 115k(GH)+87k(FH)+51k(Heal)+62k(PWS)+45k(PoH)=360k absorb on ONE target. Impale? Wtf is impale? =)
This is insane

P.S. Inner Focus doesnt work with SS

Lvl 88 values for Gheal (without grace), so its going be much smaller than level 85

Base 47149
Spirit shell 66372
crit 7.92
mastery 27.41
haste 7.18

1.0792*1.2741*47149 = 64 830

66372/64830 = 1.02379 is the missing factor

The lvl 85 version of my char

base = 45977
Spirit Shell = 76214
crit = 6.69
Mastery = 36.86
Haste = 16.66

1.0669*1.3686*45977 = 67 134

76214/67134 = 1.13525 is the missing factor.

Now lets try something different.

Crit averaged heal = base*[1+(1+0.6*(1+mastery))*crit]

For the level 88 version --> Crit averaged heal = 54 045.6

Apply mastery directly to that and you get 54 045.6*1.2741 = 68860 we expect 66372

66372/68860 = 0.96386871914

For the level 85 version --> Crit averaged heal = 51 578.6

apply mastery directly: 51 578.6*1.3686 = 70 590.5 we expect 76214

76214/70590.5 = 1.079663694123

So this isn't it either but its closer. It appears though that high mastery produces more a deviation, so mastery is double dipping somewhere. I will try a few more things later on.

Incidentally for PoH @ lvl 88 I get a 25813 spirit shell without grace and 33577 with grace. So PoH spirit shell benefits from grace just like normal PoH does, whereas in the previous form of spirit shell it ignored grace.

My gut feeling is that the amount of the absorb with some form of crit scaling is calculated first and then mastery is directly applied to it.

I discovered exact formula for SS
For Direct Heals:
SS_Absorb=AvgHeal*(1+Crit)*(1+Mastery)*(1+0,3*Crit)
For PoH:
SS_Absorb=AvgHeal*(1+Crit)*(1+Mastery)*1.3

This works for my level 88 values, but not for my lvl 85 values.

1.0669*1.3686*45977 = 67134


67134*(1+0.3*0.0669) = 68481.4, but the value I actually get is 76214.

I am going to use reforging to change my crit and mastery and plot all the values so we can work out exactly how they all vary.

Ok, I will provide the way, how you can calculate it properly to be sure, that formula is 100% legit.
Take off weapon, cloak and trinket that can proc with Lightweave, Power Torrent or something.
Look at your tooltip of any of heals. For example FH:

Then look at your stats:

Make some calculations
SS=29348 (AvgHeal from tooltip) *(1+0.1609) (Crit) *(1+0.3785) (Mastery) *(1+0.3*0.1609) (Aegis Part) =
29348*1.1609*1.3785*(1+0.3*0.1609)=49233

Then turn on SS and cast that heal once.


Voila

Hmmm, this is very odd. The values I posted from my level 85 priest are not with power torrent or grace and the formula does not work for them....

Level 85: Mastery 36.86 -- Base heal (greater Heal) 45977

Crit 6.69 --> 76214
Crit 8.71 --> 77988
Crit 10.11 --> 79230
Crit 11.05 --> 80071


Crit 6.69 --> 45977*(1+0.0669)*(1+0.3686)*(1+0.3*0.0669) = 68481.12026 --> Expect 76214

Crit 8.71 --> 45977*(1+0.0871)*(1+0.3686)*(1+0.3*0.0871) = 70192.2310 --> Expect 77988

Crit 10.11 --> 45977*(1+0.1011)*(1+0.3686)*(1+0.3*0.1011) = 71387.18778 --> expect 79230

Also I get a straight line, but when I vary mastery I don't. When I get home I will go repeat this with my level 88 priest, to see if its the same.
========

Edit: If I plot the values from your formula I get

y = 84954x + 62796
R² = 1

So the crit range I am testing is not large enough to make the plot deviate significantly from linearity.

However we have an easy way to test the formula. The y intercept should be base*(1+mastery). So 45977*(1+0.3686) = 62924.1222

This does not match intercept from lvl 85 values. There may be some anomaly that I missed with my level 85 priest.

The 1st derivative with crit of your formula is base*(1.3+0.6crit)(1+mastery). For 0.1011 crit this is 85618.33611

From plotting my values I expect 89468.

So neither the slope nor the intercept match. However if there is some anomaly giving me a fixed boost to the absorb everywhere, both the intercept and the slope should deviate by the same factor.

89468/85618.33611 = 1.044963078

70293/62924.1222 = 1.11710736

So that is not true either. That means the anomaly is not because there is some fixed constant factor affecting the results. Its clearly following a different formula.

Noway. I tested it with various crit and mastery rating via reforge haste to something. And always have results with ±1 precision.
I dont know why its so different for you and me. We need 3rd person to check that all.

Just checked it with various stats for GH (always checked for FH before) and formula above is right for GH too. So definitely you make mistake somewhere. All we need - to find it.

Spirit Shell was changed in last build. Now, when you trigger it up, you dont lose ability to heal and generate Aegis (bug?), but all heals additionaly stack buff "Spirit Shell" on their target. Which stacks to 60% of your max hp!!!

Now it is more overpowered then ever before. I think heal part will be removed, because Disc Priest just have tremendous amount of heal for 15sec every 60sec. But you cant stack 400k absorb on one target (but who really thought that was not broken mechanic?)
Formula seems unchanged.

And regen formula changed too.
OOC_Regen=2000+Spirit*1,1286987
IC_Regen=2000+Spirit*1,1286987*%Meditation

That means, that if you are naked, you have 2056 mp5 IC_Regen as Disc (199 Spirit), and if you are geared like a king, you have 2791 mp5 as Disc (2805 Spirit). Plus Rapture ofc. But anyway, Blizzard just can make Meditation for Disc 0% because difference between 2056 and 2791 not so big -_-

Given the addition of penance into the list of spells that work with atonement, and the buff to the damage dealt by penance, what is the optimal usage of the spells holy fire, smite, and penance? Penance and holy fire are both on 10 second cooldowns. Holy fire can be made instant via a glyph. The dot left behind by holy fire lasts 7 seconds and, when glyphed, increases smite damage 20 percent.

At first glance, It seems like the best usage would be...
Holy Fire > Smite (with holyfire debuff) > Penance > Smite

And as an opener, it might be a good idea to penance first and then holy fire just to build up evangelism stacks quickly.
What do you guys think?

Also on a side note, greater heal seems to have been buffed greatly on beta. With archangel, my trinket, etc, I can crit heal for roughly my full hp ~140k, which is at least 30% more than I can recall doing on live. Perhaps I am mistaken.

I think penance/holy fire/smite ... is better for stacking/manacost/easier gameplay/efficiency of smite dps.