Anything that slows down the purchase process is a bad thing.
Example: Does your web shopping cart ask what kind of credit card the customer is using? Your form can figure it out from the card number.
One less step = faster checkout = happier customer = more word of mouth and repeat visits.
Step 1: Find and remove anything between you and the customer’s money.
Step 2: Are your programmers thinking about less work for the customer or for themselves?