I simply do not see this. Just ran a test on a dummy on live, and the data is below

Data

1935 SP, no proccing gear, no Fel Armor
Incinerate Tooltip : 698-812 + 174-203 with Immolate on target (note: tooltip includes contribution from % scaling talents like Emberstorm, but not spell power)

First 10 non-crit Incinerates w/o Immolate
2701
2707
2796
2722
2741
2785
2721
2695
2701
2690
Average - 2725.9

First 10 non-crit Incinerates w/ Immolate
2936
2915
2963
2942
2939
2876
2997
2913
2957
2950
Average 2938.8

Difference of 212.9

We would expect a difference of 188.5

So either the Spell Power coefficient for the extra Incinerate damage is .0126, or it is 0 and the difference is due to statistical noise of the small sample. I am inclined to believe the latter.

I'm hoping they just worded the F&B badly, otherwise this whole mini-patch is nothing but a hearty Deep Destro nerf.

Edit: Included data.

Did you notice that it used to be 15 seconds of your immolate, so they clipped 3 seconds off it and that will be another damage nerf to conflag damage.

Conflag was already hotfixed to be caculated based on 70% of the immolate cast (so 10.5 out of 15 seconds), so this would actually be a slight buff back up to 80% (12/15).

Not necessarily. It used to be 70% of 15 seconds of immolate. Now we've lost 15% from F&B, but gained 2.5sec of immo damage to conflag.

0.7 * (Immo * 1.15) = 0.805 * immo

Immo * 12 / 15 = 0.8 immo

So conflag damage should remain about the same. It might be a dps loss to cast it on cooldown though, now that it consumes the immo effect.

To quote GC:
"It looks to me like you are just multiplying the "damage" of Incinerate not the "bonus damage". I know this business gets jargony. Consider it like this: Incinerate does X damage. If cast on a target debuffed by Immolate, it does 125% of X. If cast on a target debuffed by Immolate with Fire and Brimstone, it does 155% of X. It's confusing because the Incinerate tooltip is trying to be too smart and tell you the additional damage done, not the multiplier.

Say Incinerate does 1000 damage. With Immolate, it does 1250 damage. Talented with Fire and Brimstone and Immolate it does 1550 damage. So the talent could just say "Incinerate hits 24% harder."

We'll try and come up with text which makes this more clear."

delete

Yes, thus conflag is back to clipping the end off your immolate. The 10% bonus to the next 3 destro spells cast should compensate for the damage lost by clipping. I'm slightly bummed that you will need to waste one of those charges on the new immolate. What would be interesting is if they some how managed to have the 10% propogate through to the entire spell (the initial damage as well as the entire dot's duration) but I highly doubt this is the case.

Sadly it doesnt, the 10% only affects the initial hit of the immolate, which has no affect on the subsequent conflag at all.

How do you know that? It's simple logic that the 10% increased damage should also affect immolate's dot. Which, in turn, affects conflag's damage.

Some info on how Incinerate works from GC

World of Warcraft - English (NA) Forums -> Conflag Change Clarification

So instead of going from 174-203 to 226-263, it should be around 393-446 extra damage.

Actually GC just posted that the dot DOES increase 10% aswell, so conflag should also see a 10% increase for all subsequent ones after the first. (assuming you don't miss any conflags)