If seller quotes the price, it is up to seller to edit. Ebay would only get it wrong if they made changes.
It used to be POSTAGE AND PACKING so a 2p increase would be covered, but if using Simple postage, packaging has to be covered in item price and ebay can increase the buyers fee by a few pence, but millions of pennies increase profits.
Looking at your listings, all avoid simple postage, just use bulk edit to increase to 87p.