sorry but this part (and only this) is not true!
Enable the RoF settings (except rof all in range, also not in combat)
best fight to so the difference is sha of pride (hc), the warlock which is playing without RoF is doin up to 150k LESS dps than the Warlock with RoF, and this is not the dps on the adds... it is the ember generation through RoF (this was lowered somewhere mid MoP but is still a DPS increase) which makes u able to cast more SB/CB
not using RoF is in all cases a bad idea
i tried it / compared with another destruction warlock in my raidgroup, we are basicly from the same gear (identical items, the one has some more heroic warforged, the other has more heroic normals, but all in all we are from same gear (same trinkets,weapons,rings,cloak) ... and i'm not able to do the same dps as he is doin when i disable RoFing
I have everything disabled, do you mind telling me your Item level and avg dps in destro?
On Galakras the adds i can do up to 1mil dps with destro and my base settings have disabled everything in the RoF section as i see no point in having it when my rotation have to use it, it can stop a chaos bolt from firing in time if i pop my Burst mode.
Also i use the multistrike trinket and its not really worth the 33% chance of hitting being a rain of fire dmg compared to a chaos bolt or an 1.5mil incinerate.
You can record a video for me so i can study it a bit more, and i can do the same to you so we can compare eachother.
Also remember that, when the rotation switch to Multi-target it will use the rain of fire no matter what.
But for singletarget i dont see any point in canceling a chaosbolt that probably would have hit for 2-3mil+ and your trinket is about to run out and that rain of fire will not make up for a chaos bolt

I have been trying a lot of things with the rotation enable it disable it and the settings i got for now feels better unticked than ticked.
I feel more improvement if its unticked than ticked

Also you got my settings so you can see for yourself i got it unticked.