Noted. OK, buy them separate and be done. Things like that happen in retail. Take advantage where possible.
That reminds me of a story my mother used to tell. She grew up in Lebanon, Mo during the depression. The local grocer (only one at the time) would sell canned vegetables $ .08 each or 3 for $ 25. When sent to the store, grandmother gave her enough money to purchase only two at a time, to save the penny. Inaccurate (intention or otherwise) pricing has been around for a long time.