Never knew about VAS. I guess I just need to lobby the store to implement the protocol then. Probably fat chance they'd actually implement it though.

You'd think it would be a no-brainer to improve the checkout process like this, but perhaps Apple's terms are unfavorable to the stores.

Anecdotally, VAS is great when it works. Seems to work reliably enough for me at Walgreens and Jimmy Johns as two examples. (Though I often forget it works at Walgreens because they heavily encourage the two-step procedure because the cashier likes to make sure you have the loyalty card for some reason before finalizing the total, even when no savings would have been involved.)