Switching payment method for deposit to DVA when using a TA

[havaneselover]

Has anyone who uses a TA switched their payment method for their deposit to DVA? I know you can switch your payment method after the fact and get the original payment method credited back, I'd just love to do it with DVA and wasn't sure if that's possible. I want to do this because when I booked on board in April I didn't have extra gift cards but I'd rather save 20% on the $400 deposit than the 3% I saved using my credit card. And I want to use DVA so I get to $4000 total spent ($80 in gift cards).