You can only use one gift card up to $1000 at a time. I had to call customer service to pay for my APs via gift card because they required more than $1000 each. If your tickets are under $1000, but over $1000 together, then just two separate transactions for each ticket.
I thought that was a weird glitch with looking at them on my phone instead of a computer. Maybe they’re assuming people are going to be looking at shorter visits? APs don’t seem to be available as an alternative.