"IMHO, If there really was prior art that would defeat the 336, it would have been found long ago"
You would sure think so. It is almost like:
Requestor: We think the patent in question is invalid because we used the prior teachings of A,B,C in developng our product which is the same technology as the patent in question.
USPTO: But the teachings of A,B,C don't relate to the patent in question.
Requestor: Oh yeah, forgot, we also used prior teachings of D,E,F in developng our product which is the same technology as the patent in question.
USPTO: But the teachings of D,E,F also do not relate to the patent in question.
Requestor: Oh, well just keep going down the alphabet until we find something that is at least close.
I know it isn't that simplistic and I exagerated the above, but the one thing I do remember from the few business law courses I took in college, it isn't about wrong or right, it's about taking the path that costs the company the least. So again, stall tactic? IMO probably. They have more money than we do, so time is on their side IMO.
Good luck everyone.