Rick,
I'm not positive so hopefully someone will check-in if I'm incorrect. I think the 2 limiting auction attributes:
1) Any bids on the item, and/or
2) Within the last 12 hours of the auction
...no changes can be made(?), except MAYBE to cancel/end early.
It would also seem to make sense that the seller can only make a shorter length auction to a longer one i.e. make a 3-day auction into a 5, 7, or 9-day auction, or a 5-day to a 7-day, etc. I don't think a 9-day can be lengthened by ANOTHER 9-days, etc.
I agree, it is something the AS service needs to be reprogrammed to check, perhaps during the last 3 minute "Lock up" period before the snipe is scheduled to fire. Let's face it, this is probably a VERY RARE occurance in the grand scheme of things, so the vast majority of snipers will be unaffected by this "bug".
Jabbergah