DOFD is Date of First Delinquency. That's important because it's the starting gun for FICO scoring. If the DOFD is greater than 24 months ago, I would think twice about pushing for any deletion of the OC's TL, because there is a chance that this TL is only minimally impacting FICO. In many cases, OC TL's can actually help FICO scores by raising the average age of accounts, total number of accounts, being in the mix of a variety of credit, etc.
Obviously after all the 623's are done, it's helpful to see a fresh set of hard copy credit reports. That will show what changes if any were made and from there....the fun begins.
I'd wait and see what the 623 turns up from the JDB. Lay the JDB response next to the OC response and that will paint a very interesting picture!