Chiam,
You are making a lot of assumptions that are not factually borne out. And bottom line is, you seem to have a gripe with Rabbeim getting some sort of break on tuition.
You keep saying parsonage. It’s not parsonage. Totally different concept.
Not everything can be based on a strict mathematical formula. Sure, there is math, but that is not all that is taken into account when determining tuition obligations. It’s not an easy or fun job for those who have to make the decisions.
DO carp about college tuition which often is many multiples of Yeshiva tuition. Even with endowments spinning off plenty of money and even with class being only 12 hours a week for 30 weeks of the year?