40 hours per student? 150 students per year?
Do the math. 40 hours is one work week. There are only 52 weeks in the year.
How tired of taxes do you want to be?
40 hours per student? 150 students per year?
That many hours are not required per student for a teacher to keep records because the teacher's students are in the same class covering the same subjects and material. For homeschool families, the children are (usually) working at different levels with different books and materials.
Also, different people are contributing to a student's school records. Homeschool records can be far more cumbersome, depending on state requirements, and one parent is keeping track of everything - all subjects.
Now, if the students each were doing individual work in school, as I see your post #46 mentions above, the teachers might have some extra work to do. I do think it could be manageable, though, depending on the system and how it is set up. I remember posting an article here about a school that decided to try it, as a matter of fact.
Btw, in my high school many moons ago, my math classes were self-teaching, independent study classes. We taught ourselves algebra and geometry and worked independently. Each student tested whenever ready. Only one teacher would sit in the class, available to answer questions if needed. So, though we were working and progressing individually, the teacher only had to make check marks and write down scores. Most of the time, the teacher sat there bored.