my experience (semi-limited) has borne out the anecdotal experiences related to me: end of month is when most recurring transactions are due, beginning of the month is when the overdue folk are scrambling to get 'em done. rest of the month is mostly just the new or one-time actions.
the coupla times I've had to go between the 27th - 5th of the month (which I've tried to avoid), I found much longer lines than the times I've shot for 10th - 20th of the month... so it seems to hold true.
(at least @ the Brockton & Beverly RMVs...)
YMMV...
