When adjusting billing information on the Checkout step of an Event Registration form, the adjustments do not carry over to the payment page.
We are currently evaluating this issue for a fix in a future service pack.
Steps to Duplicate
1. Create a new Event Registration form(not the classic form) and add it to a page. 2. View the page. 3. Fill the form out with an attendee and choose an event for the attendee to attend. 4. On the Checkout step of the form, mark the checkbox labeled, "Use an attendee's contact info for billing" and select the attendee registered for the event. 5. Make a change to the information listed for the billing information. 6. Click Continue to move to the payment page.