I paid off my smallest SL of around 1500 (orig bal 2k vs big consolidated SL of 45k) and didn't notice a bump on scores.
However my installment debt has been out of whack for a few months. I turned in one lease, took out a new lease, turned it in after a month and did a new (3rd) lease on a different car. Both new leases along with my orig lease were showing for awhile.
Do you have any other installment debt?