In the last few weeks I have found that if a buyer uses the Cart so they can request a combined postage invoice ebay very promptly tells them that "this seller does not allow combined postage" even when they expressly say they do.

Another favourite is "ebay does not allow combined postage when a seller has Immediate Payment selected".   Too bad if the seller has no idea that they have had immediate payment foisted on them.

Just a bit more money for ebay at the expense of both buyers and sellers.