I've scoured this thread and thought I knew the answer but I have recently been told I should be reforging hit over haste until I reach white hit cap for combat to get the most benefit.

Us this the case or have I been misinformed?

I would think that it was the mastery buff that was responsible for your increase. I had a smiliar experience to yours. I went up about 2k dps on Saurfang and my instant poison damage was quite a bit higher than usual for most of my parses for that fight. I think my mastery went from approximately 33% before patch to 46% after. That's a big number. My envenom numbers look pretty much the same this week.

Just out of curiosity,does anyone have any rough estimates on Combat's current mastery EP after the buff ?

the mastery stat value is 1.9 at the first page which is same before the last 4.0.3a patch...
Is it still same stat value after newly getting mastery buff ?

May I ask if you managed to fix Main Gauche proc sources? When I tried to do so, it created a cycle in the calculations (MG procs generate energy, more energy means more specials, more specials means more MG procs) that the sheet does not accept.

At the end I tried to experiment with some hardcoded values - I was manually increasing number attacks in MG proc formula to simulate that it procs not only from autoattacks but from specials as well. With my current gear (assuming that we are expertise and spell hit capped), mastery surpassed crit, white hit and haste when I multiplied number of attacks by 1.45, 1.9 and 3.0 respectively.

When I check rows 62-64 in the calculation sheet, I can see that I do approximately 51.50 MH attacks/minute, 36.65 SS+RvS/minute and 8.55 finishers/minute. That means that SS's+RvS's+finishers are already increasing number of attacks by 88%. As far as I know, MG can proc from MH poison application as well, so in theory, total number of attacks affecting MG procs is indeed at least 1.9 times bigger than before the fix.

I am aware that my estimations are a bit crude, but unless there is some major overlook in my logic, I am convinced that current value of mastery for combat is slightly above the crit value, but certainly still below the haste value. That would make mastery the second stat to reforge to, for those cases when we can't reforge to haste.

I did correct for MG proccing on specials and autoattacks, yes. Since the spreadsheet is currently set up in a manner that creates recursion, I added a new row of MG procs/minute to use in calculating energy regeneration, and manually edited those values to match the changing values of the MG ppm (two or three manual edits and recalculations were typically enough to stabilize the values to more decimal places than are probably actually needed).

As for reforging to mastery--the results still showed white hit being the preferred reforging stat for Combat when haste is unavailable. Mastery is indeed slightly above crit, though, and thus won't be an avoid-at-all-costs stat when it starts showing up on gear.