no didn't overpay...when you pay online there is a small fee ($3) extra ontop of the ticket amount. ( example $52 (ticket) + $3 (online fee) = $55
then i believe they give you a reference number...
if they forget to process the ticket you get the ticket amount back not the online fee. (i believe they have 10 days to process the ticket then it gets tossed out but i could be wrong)