The change to offer to store the payment details for the merchant to enable automatic charging for recurring charges was checked by default. I didn't notice this and as a result, even though I tried to include a custom tip, the payment amount WOULD NOT UPDATE. I finally figured out that I had to UNCHECK the save details option to get the payment amount on the screen to update to include the tip. I am not saying that having the option is wrong, but to have saving details the default is A VERY VERY BAD IDEA.