hey mg!
I have been in the collection industry for about 8 years or so. I have come up with similar situation as you. I have found that is is very important to make a sliding scale on results. As you know some people are excellent collectors some are not. First consider that you may be paying too much per hour to start and comission may be too low.
I know a guy who knows a guy that ran a collection dept for one of the big 3 automakers's credit arm. this is what they did.
per month
collected comm rate
0-2000 = .01
2001 to 5000 = .02
5000 to 10000 = .035
10001 to 25000 = .035 + 2 tickets to vegas
25001 to 50000 = .035 + 2 ticket to vegas + 1000 cash
50000 to 100000 = .035 + 2 ticket to vegas + 5000 cash
now these numbers are not accurate, they are just an illistration of how to motivate a collection staff. when someone hits a big bonus pay it in cash, in front of the rest of the staff (like at a staff meeting) you will get more bang for the buck.
feel free to email me
jpkruse@yahoo.com