Avoid excess divides in the amount < min bucket scoring loop

Avoid excess divides in the amount < min bucket scoring loop

When we iterate over buckets in the "the amount we're sending is
smaller than the minimum bucket we're looking at", there is no need
to divide by the total points tracked until we've summed all the
buckets. Here we pull that divide out to the end, removing one of
the hottest single instructions in our scoring logic.