I'm not sure I got your comment right, but I obviously left out one factor in my earlier message in this thread. Since you can change the ticket prices monthly, there is no way of knowing how much the season ticket holders should pay you at the beginning of the season (assuming they would pay only once). This is probably the biggest reason behind the decision to have the STH's pay their tickets on game day.
(Perhaps at some point in the future a separate season ticket price will be implemented. Personally, I see no strong reason for that from the gameplay point of view, though.)