I can't covet my latest payout either....i sent them an email but I havent heard back.....
er...that's convert not covet...LOL
On my PayPal, it shows the GBP but, it also displays USD* available. What looks like is happening is that it's being sent from PA in GBP. Paypal isn't converting it until it needs to be used. The * states that that value is at current conversion rates. Basically, you don't have to convert it. It will happen when you use/withdraw/transfer it.
EDIT It's actually better this way. You can withdraw money from PA at any time, then wait until the USD is strong, to actually transfer it from paypal.