Your accord may, or may not have been rejected due to "turf protectionism", but, more likely it was because back then there was no repeatable and defined process. We have it now, and it makes things much more objective. THe prod folks have no such thing that I am aware of, so results might be fine, or might not be fine, but perception will always be the issue.

Convince the Prod Ad Hoc to devise and use a real repeatable process, and I suggest you'd have more confidence in their decisions. (THe ITAC recently forward our process to them for a look..,maybe they can adapt or use the basic framework?)