I suggest that PFD works best on OCs, and that the CA hears that you're interested in paying and thinks that they can say "we'll mark it paid in full" and you'll be a bumpkin uninformed consumer and think that by doing so you've improved your credit. 

I think "paid in full" on a report is such a scam-- since it is still derogatory info on your report.  You really have no incentive to pay unless they delete, since they've already taken as much action as they are likely ever going to take.