You just checked posts written in the last two days (September 29th and September 30th) to see how miuch merit they got, right?
Yes, that is absolutely right.
I am asking because you would have to check all posts written last month in order to get correct number because some post from lets say September 10th might have been merited on September 30th and you would have missed it if you only checked those last few days, or post from September 29th might have been merited on October 2nd which then doesn't count towards September. For that reason its best to wait for Friday and check Merit Dashboard to get exact numbers.
Hmm this is a valid point, but lets suppose on this friday, 06th October, the the dashbaord is updated and after that there is again some old posts being merited and the probability of this increases more becasue of this thread [Merit] Help posts in local boards that did not receive enough merits by hugeblack. So this merit count per month can increase at any time, the best part of this is that it cannot decrease.