The customer orders from their phone. Your server sets the price.
The phone sends what and how many, never how much it costs. Price and VAT rate come from the server, out of your recipe costing, so an old menu on an old phone cannot undercharge.
One QR per table and the menu opens on the customer's phone, with nothing to install and no signup. What matters is what you cannot see: the phone sends what they want and how many, never how much it costs.
Price and VAT rate come from the server, out of your costed recipe or your catalogue, so a stale menu on a stale screen cannot undercharge.
You do not have to switch everything on. Tell us how you work and we will tell you where to start. ATAZEL is in testing: write to [email protected].