in my experiance, supposing u had listed some items in month ov nov, u will be charged in december, entire dec they will reflect it on ur seller page.
supposing u pay it immediately in dec itself... even then it remains the same way..
in jan i.e. next month, they update your account with previous credit and debit balances.. so i guess your account will take month to update itself.
wait and watch.
regs
kshitij