And if so, does the extra money go towards my next payment or the end cost? For example I have a $300 phone on a $13/month tab plan. On my first month I pay $20 instead of $13. Is my next payment $6? Or is my final cost $280, $7 less than it would have been had I paid the required amount. I have irregular employment, so it would be nice to pay for the next three months in advance if needed.