When my parents started teaching, the early '60s, there was a similar "equation" when it came to a teacher's level of education.
It went something like this:
Ed. Specialist Degree / Doctorate = Administrator
Master's Degree = HS teacher
Anything lower than Master's = K-8
If you had a Master's or higher, and were in the classroom at the K-8 level, it was assumed that there was something wrong with you.