I do use that too but I'm not really sure if that's accurate enough. For me I always leave like 15mb++ unuse so that I won't get overcharge but you never know when Maxis start next month charging! Btw, if I want to cancel my contract with Maxis, what are the penalties I will be facing? The contract is until may and data plan is 500mb and I'm intended to move my number to another service.