Real Time deliveries do not use your zip-code delivery prices. When a Real Time cart is set to delivery, Sprwt requests a delivery quote from Uber Direct for the trip from your kitchen address to the customer's address and charges:

Uber quote + Uber Direct Sprwt Fee above Quote (default 3) + Uber Direct Kitchen Fee above Quote (default 0.3)

The quote ID and the two extra fees are stored on the order so they can be used later as the cancellation fee if the order is cancelled after preparation started. The checkout page also shows the order date together with the chosen order time in the delivery information block.