Well, you also have to consider the following:

The Initial damage of Shadowflame is Shadow damage (not boosted) but the DoT is Fire damage (boosted).
Shadowburn is shadow damage.

A reasonable proportion of damage also comes directly from the Imp's Firebolt. The Imp scales with our crit, but I suspect not with our fire boosting effects. I suspect that the Infernal's melee and immolation aura and Ebon Imp's melee will scale with our crit (if they scale at all) but are also unlikely to do so with our Fire damage boosting effects.

And to clarify:

Chaos Bolt does not "count as" fire damage: it is Fire damage.
Fel Flame is Shadowflame damage so is boosted by fire damage boosting effects.

The scale factors are a useful tool but can only be directly applied to the situation from which they were generated. Especially when they're as close together as Mastery and Crit are currently simmed (Crit is <10% ahead in the 372 profile) it's something you could easily change in the act of gearing for it.

While working on my debuff tracking addon, I wanted to check how did haste and Fel Flame refreshing Immolate worked. I made a little script which compared expiration time on immolate both before and after refresh, and printed the difference in the chat along with the timestamp. I casted fel flame with 2-5 sec left on the Immolate debuff to avoid losing extra seconds due to debuff not being able to be extended beyond certain time (base dot duration including hasted extra ticks and/or glyph).

I was at 0 haste on the image to the left, some haste and Dark Intent on the second and my full pve gear + dark intent on the right



The script sometimes doesn't register the time properly and shows abnormal number of ticks gained, which is not correct, but the timestamps surely are.

On the image to the left you can see me keeping Immolate up for 243+ seconds with 30 casts of Fel Flame which translates into average 8.1 sec per cast or 2.7 ticks per cast.

With 906 haste + dark intent on the second image I had 29 casts during 223 seconds which is 7.69 sec per cast or (at 2.801 sec per tick) 2.75 ticks average.

At 2.531 sec time between ticks 29 casts translated into over 219 seconds of immolate uptime, or 7.55 sec per cast (2.98 ticks per cast).

Of course, numbers like 2.03 or 1.96 ticks actually get rounded to 2 ticks, with the debuff expiration matching the very last of them. I omitted the verbose output to save space).

I tried using demonology with felguard demon soul, got the following results:



The first two refreshes are those I could manage to cast while demon soul was still up. They both gave 3 ticks. Third refresh was already after demon soul expired. The extra time (6.29 seconds) resembles replacing 3x2.267s ticks (demon soul) with 2.607 ones and appending 2 more ticks to the end: 5*2,607-3*2,267=6,234 . The rest of refreshes gave 3 ticks.

I'm not sure what's the exact algorithm the server uses to decide how many ticks to append to the end of your dot. Any thoughts on why do I get 3 tick refreshes even with 0 haste (9 extra seconds)? I wonder if 4-tick extension can be earned on higher gear levels or under heroism, was unable to convince a shaman to help me at this time.

EDIT: allright, got a shaman to help me. With wrath of air totem and heroism I've been able to get 4-tick immolate extension, while in demonology spec with demon soul: felguard. screenie here:



first 2 refreshes are during demon soul+heroism, 3 and 4 during remaining heroism and the rest after both expired.

I'm kind of scratching my head on some of the aspects of our priority.

Usually i start a fight with Soulfire (precast) immolate-conflag-corruption-BoD-Chaos bolt- (demon soul) Incinerate-incinerate-incinerate and then hardcast another soulfire with 4-5 seconds left on the buff (to compensate for travel time).

Im not sure if i'm overestimating the importance of ISF though, as it seems like trying to micromanage it and keep it up 100% of the time isnt optimizing my dps. with my gear (354 ilvl) im doing around15-16k on the dummy (self buffed, food buff) but every now and again i'll eek out a consistant 17k and cant figure out where its comming from.

Is it best to try and keep ISF up all the time, or is it okay to let it drop off for a few seconds in order to make sure you get off conflag as soon as its CD is over, or refresh Immolate before it expires.

I've done some testing on a dummy, no buffs, trinkets off. I see, that dots do damage not from the buffs on target/player when they tick, but from what buffs were active when they were casted.
Results were consistent:

Corruption ticks:
1354 dmg when cast without ISF, no change when I got ISF up without recasting corr.
1462 dmg when cast with ISF up, no matter if the buff got off while corruption was on

Immolate ticks:
2844 same as above
3072 same as above

So my question is
The scenario: ISF got ~3 seconds left. Immolate got ~1 second and corruption is either off or have about 1 second letf as well. You just finished casting Incinerate or whatever.
Wouldn't it be better to refresh Immolate and corruption and thereby letting them tick with full dmg (as ISF was up when when they were cast) while hardcasting SoulFire afterwards - even though ISF would be off for about 2 seconds? Instead of hardcasting soulfire and getting 100% uptime on the buff, but missing ~2½ seconds on immolate and corruption ticks?
The uptime on ISF doesn't really matter, as long as any other spell you cast is cast with ISF active?

EDIT: typos

Just two mistakes in the BiS:

Stormwake and Bell aren't linked to their heroic versions.

I am using item tags to link, and have not found a way to control which version it will pick (normal/heroic). I'll have to link them directly, but haven't had the chance to yet.

I guess your spell priority is messed up alot if you are getting in such a situation (at least in a patch work like encounter). Why would one cast incinerate while immolate is <2s AND corruption off?
One Tick of Immolate / Corruption accounts for lot more than 8% dmg on soulfire and still would be more than an 8% soulfire + 8% of a single corruption tick and 8% of a single immolate tick; even 8% of the full duration is a lesser dps loss than 1 tick (out of 7 or 8).

You can refresh both dots the moment your Chaos Bolt is out, so you would neither sacrifice dot uptime nor active casting time nor clip any ticks.

(So with 2 secs left on immolate, i can cast it (casttime close to 1 sec) without clipping ticks? doubt it)

That wasn't really constructive.

So with immolate after CB, it would look like:

3,87 - 2,47: Incinerate (with backdraft on and my haste on dummy)
2,55 - 1,40: Chaos Bolt (Corr/immo still up, immo ~2 secs left, corr 1-2 secs left)
1,40 - 0,06: immolate+Corruption (As immolate had ~2 secs left at the start of the cast, it has about 0,7 secs left when it lands.)

Think this sums it up, if you've got any further comments, please read through the conversation again. I've got my original questions answered, so I'll stop posting useless stuff now

Immolate: 15s duration; 5 ticks baseline; 3s interval baseline - refreshing it <2s won't clip any dots, you get an immolate with ~17s and get an additional tick within the new duration (the last tick of your old immolate)
Corruption: 18s duration; 6 ticks baseline; 3s interval baseline - nearly the same goes for corruption

As noted elsewhere, whether it's worth recasting DoTs in the presence of additional buffs is difficult to determine ahead of time to get a piece of "when X procs, you should always recast Y" style advice that is always correct because there are a lot of factors involved and the answer may change rapidly in real-time. It would be possible to make an arbitrarily complex decision process in Simcraft, or perhaps in-game if you were willing to write/find an add-on to take the information into account, but other than that you'll have to use a rule of thumb, such as the one you're already using. It's fairly easy to test such schemes in Simcraft, but I would suggest only testing something you think you could actually perform in the heat of battle. You'll note that the current Simcraft thread priority lists do not attempt to make use of such buffs in this way.

Procs are usually taken into account at the end of a cast. An exception to this rule is that haste effects and casting time effects must be present before you start casting to affect the cast itself (i.e. if you proc haste in the middle of a cast, it will not make that cast quicker.) If a haste proc occurs while casting a DoT (such as Immolate) then the cast itself will not benefit, but the DoT does.

When you clip a DoT it adds the duration after the next tick of the current DoT, which means that the perfect time (from an uptime & efficiency point of view) to refresh a DoT is any time between its second to last and last tick, remembering to account for the effect of Haste on tick interval. For example, Immolate ticks every 3 seconds and is effected by haste, so with 0 haste the perfect time to re-apply it is within 3 seconds of the end of the duration, and with 50% haste it's any time within 2 seconds of the end, etc.