Demerit points, assigned to any conviction, or finding of not innocent in the case of a juvenile, shall be valid for a period of two years from the date the offense was committed. Demerit points used prior to the termination of the two-year period as the basis for suspension, revocation, probation, or other action which extends beyond the two-year period shall remain valid until the suspension, revocation, probationary period, or other action has terminated.