It depends on how it is used.
If the customer had made all the orders, and the waiter is making a confirmation going through the orders, and if the non-past tense is used, then it will sound like the waiter simply forgot the order and is asking for the second time with a guess. That can be rude. By using the past tense, it expresses that the customer's selection/order is already an established fact.
If the past tense is used out of the blue, then it sounds a little strange. It may be a misuse, wrongly expanded from the usage just mentioned above, but still, a possible interpretation to this is that the waiter is standing on the point of view of the second person. From the second person's point of view, the choice was probably already made by the time the waiter is asking, and hence the past tense is used. It is sometimes considered polite to talk from the second person's point of view.