Subscription Rollover Issue

We are running the subscription rollover in test at the moment and for the most part its working, but we're getting a very small number of orders that refuse to generate rollover orders. We believe the common denominator is that the original orders from this past year were altered in some fashion, such as package seats were moved before printing, or exchanged is that order or another order, or the customer account was merged into another account. But only thing is that there were other orders where things like that took place that still rolled over just fine. The actual error message was: "MOS 13 is not assigned or is not valid for date." MOS 13 would be our web subscription MOS. Anyone encountered this issue before?