Distributing such a huge amount of merits with some kind of meaning is, of course, an enormous task!
Normally I would think so as well, but oddly enough it wasn't last month. I know the reason, and I've said it a few times already: I got way more requests to review post histories than I usually do, and more than a few of them were good writers with a lot of posts, so it was easy to blow through every single sMerit I had.
If I were to try to hit that 1600+ number just by meriting the posts I read, I'd fail miserably.