Due to new collections laws, some collections agencies get paid a flat fee to do the collections - and they get this flat fee whether or not they collect any money, and they get the flat fee no matter how many or how few collection accounts they are given.

So, a lot of times it is up to the original bill holder (hospital/doctor) and not the collections agency on whether or not to accept a settlement or payment plan...

Other collection agencies work on a precentage basis. They get paid 10% of whatever money they collect - so it's in their best intrest to collect the whole bill and not a smaller settlement offer.