Sure, but lecturing folks when they are in the midst of an emergency repair situation is not helpful. Clearly OP hasn't given the full extent of the situation but, if it is the case that a coop need an LOC draw in order to make a repair, then it is what it is. No one is short 2% since you only borrow the money that is needed (essentially the shareholders that need to loan the money) and that amount is shared amongst those who did not pay in advance. The interest cost is not incurred if the money is borrowed so there is no "2% short" as you describe.
"With the prepayment discount, the class of shareholders who can afford to prepay the assessment reap the advantages while the class of shareholders who can't afford to prepay are penalized." And this is completely fair if ALL shareholders are given the same opportunity to prepay at a discount or borrow over time. Folks who pay upfront lose their foregone interest earnings on the money. If I know I have to pay a 12,000 assessment over a year and can earn >2% monthly after tax, I would not pay upfront, even if I had the money. You wouldn't make this argument against increases in maintenance payments if a set of shareholders could afford it and another set could not.