Your only obligation to a contract is to make 12 payments per year Ie 1 payment for each calender month.When you pay that month has no bearing on if you are meeting your obligations of the agreement.
I was attempting to represent Providian's attitude, not my own. They care very much when you pay, because if you pay late, then they get another $29 (or whatever it is now) late fee to console them in this time of sorrow.