Originally Posted by
CMK10
From what I've been told by Delta they do not do buy ups at OLCI in the same way KLM and other airlines do them. If you want Business you have to pay a Business Class fare so likely you were just quoted the difference between Y and C.
I've definitely seen upgrade offers, OLCI ones and even before the checkin period. It just isn't done like KLM with DoD upgrades.