Re: I can guarantee the second sentence
It was variable fee. I don't think you can get any other type for a restaurant, and if you get one at a fixed rate I'm sure it would be a worse deal.
The way you comparison shop is to give them a spreadsheet downloaded from your POS system with your previous few months charges and they'll tell you how much they would have charged. If it was just "Visa is x%, MC is y%" it would be easy, but there's a fixed per transaction charge, which is different for the different cards and for whether it is debit or card, and whether it is card present or not present (you have "not present" charges if you take phone/online orders for pickup/delivery) before you even get into different percentage rates.