Specifically asking from a BLM perspective but this goes for any job

Ok, recently I realized I'm a half decent BLM, I get between 21.5K and 22K on SSS regularly with a ilvl 513 crit set up. Regularly get highest DPS in actual content too, even with other BLM's and SAM's (unless their ilvl is higher cause duh lol).

But here's the thing, when I'm practicing on SSS, some of the runs I do I should not be getting the DPS im getting, or at least I think I shouldn't, one run i'll clip Sharpcast (yeah, I know its a DPS gain on Sharpcast but its still not optimal) another I might forget to use a Fire 4 and just to straight to Despair, one other run I might clip a tincture, another run I might derp out and forget to cast for a second. Alll of those said runs have happened just a few minutes ago, and yet I still got near 22K on some, and on others, were I preform perfect and get all the procs for Thundercloud and Firestarter, I'll get closer to 21.5K, so whats up?