Personally I don't see why they can't just pass on the cost to the customer ? If I use paywave I get 2.5% added to my bill no big deal. If I use cash or eftpos it is the original price. PB tech do it.
Or have a marked price and anyone who uses cash or eftpos gets a 2.5% discount at checkout. Anyone uses paywave pays the sticker price.
Is this technically possible with the current EFTPOS machines? At the moment, it displays a single price before you select your payment method (cheque account, or credit card)
I'm not aware of any terminals in NZ doing this but I have seen it in Australia. It's a lot more complex to do here.