It is totally different, but the principle of doing a discount if you pay up front for a service that ties you in to one business is found all over the place. It's the same thing. You could pay £800 for a service plan, and have a horrendous experience, but you're still tied to that dealer. In terms of a business model, they're all fairly much of a muchness no matter what business you're in. provide good service, make good money, that's it.
Of course it's for the business's benefit, otherwise it's not a business, it's a charity. If it was horrendous, there would always be a way to get your money back (unless, of course, the school closed - but how often has that happened, compared to those that do this every day?)
I'm not saying that you're wrong or anything like that, not in any respect, I personally wouldn't pay a massive amount up front, but, take FIS for example. If you want to do some hour building there, you can pay up front for 25 hours and each hour would be 150 EUR. However, if you book for 50 hours, it's only 148 EUR per hour. Now, I know this equates to only £100 saved, so maybe not the best example, but it's a big company, and if I had the money, I wouldn't hesitate to do a block booking with them.