I do the same sometimes.

For exemple when I see a person who is just a few merits away to rank up
When I see a person deseves more merits than what he receives.

Just a few seconds between, because we open multiple tabs and send merits in batch. To save a few minutes.

Theymos told us something like: if we have too much merits, throw them away.
Mean to sent merits again, or more users to merits. Something to end up with zero merits left