VA-
Whenever you send PFDs, always send to the OC as well. I have many held by Absolute Collect & I know Absolute's policy is they will delete after pmt, with permission from the OC.
Also, many of your collections, if very new, could still be held by the OC and the CA has just been hired to collect, but hasn't actually bought them outright yet. Calling the OC and speaking to a supervisor in the billing department resulted in getting $1300 in collections deleted for PIF off my report, even after the CA said they could not delete.
I agree w/ your stance of addressing the newest collections first.