Wanted to pay with PayPal balance, but can't!

Hi, I have some extra cash on my PayPal account as the result of a double charge to my bank account, so I was going to use some of that to upgrade my ExpanDrive Mac 1.x to 2.0. But your ordering interface asks me to draw from a bank account or credit card again! Which made me go "meh", and drop the order.

Is there no way to just pay off a PayPal account balance? Money is money, and you already accept PayPal. What's up?