Is It Permissible to Lie to Yeshiva in Order to Get a Discount on Tuition?

I am a student at a Hesder yeshiva in my first year. My family cut off ties with my father for a few months (divorced parents) starting during my senior year of high school and finishing in the middle of this year. My mother has been able to obtain a significant discount on tuition from the yeshiva because of this and now, despite the fact that our father is back in contact with us, the discount is still in force and the yeshiva is not aware of the entire story. I want to note that: I believe that my father has the means to pay for tuition. Even when we were in contact with my father beforehand my father still did not want to pay for *school* tuition. The issue now is that after we have reunited he feels the need to be involved (even financially). My father is not religious and I don’t think he views the “burden” put on him to pay such a high sum each month positively, all the more so to a yeshiva (he respects my choice to learn in yeshiva and does not have religion or anything, and it is clear that our relationship will be ok if he refuses, but his identity with religion is not great and asking him to pay a large sum on something that is foreign to him of which he doesn’t see value seems out of place). I am also concerned about asking him for the aforementioned reasons (especially since I almost haven’t asked for anything and suddenly I am coming with a large request, as well as since I only see him about once a month because I come back from yeshiva once every two weeks to my mother most of the time. Since he lives two hours away our relationship isn’t as close as a normal father and son). On the other hand, I am concerned of stealing from yeshiva and like Mesilat Yesharim writes about theft “even if one performs a mitzvah while they are working, it isn’t considered positively but a sin for him, for a sin cannot become a mitzvah”. Another thing is that I do not think my father will view it as theft like I do, I think he will see the money as ‘wasted’ money because I am already learning in yeshiva for a lower sum and he perhaps will see this as giving the yeshiva a lot more money for no reason. I would really appreciate the help, A yeshiva student who doesn’t know what to do