The most obvious stock jiggery-pokery happens with OTO prices on easy-pays. They'll set aside a separate item number with 2p more or less than the identical item under a different item number - the explanation being that the original item price isn't divisible by 2, 3 or 4 easy pays. It's funny how the offer-priced item will sell out quickly but the usual stock item airs a day or two later with plenty of stock. OTOs are not for our benefit. At best they are a loss-leader to engender positive customer feeling; more likely they're a way for QVC to shift stock.
Mind you, it happens in high street shops I've worked for, they'll have an offer price with a % discount and when the offer ends the bulk of the stock is brought down from the stock room to the shop floor at the full-price. There's something about the smiley presentation on shopping channels that leaves viewers expecting a higher level of integrity and genuine offers than they'd see on the high street. Reading facebook those who for years sing QVC's praises voice the most acute betrayal and indignation when QVC does something they don't feel is just.
