What about the annual pass? I signed up for that and I'm thinking that might be it. I know PayPal supports monthly automatic payments like a CC (and hell, I even have the PayPal debit card so I could still do that route), so it should be supported. And maybe whatever it was, was temporary and now they support PayPal for everything.
I pay my annual pass each month with paypal manually, It can be setup to bill paypal every month but I like to control when I want to pay. -- Judge a man by the trials of his shield, not the empty reaping of his sword.