It's a fair point, but your maths are shocking. Assuming we sell half the non-season ticket seats sale available (including aways) then you're assuming that 4,000-6,000 of pre-paid season tickets on average will go unused every game!If I was going to vote today ... I'd still vote 14,000 - 16,000.
I genuinely fear that the effect of the SUPERB direct debit offer will be that a large number of season ticket purchasers will only show up when they're in the mood.
A lot of season ticket holders will treat their purchase a bit like county cricket club membership. You pay for free admission to every home league game, but only go to some of them.