Telegrok:
I dont know this for certain, but I believe the psak of R’ Moshe was a direct answer to the question of whether one could use maaser money to pay tuition and his response was that since by law one must send his child to school until the age of (I thought it was 16 – but the poster here says 17-18) 17-18 then it is a chov which can not be paid with maaser money. Of course, it is always best to look this up in the Igros and not rely on my brief synopsis of it.