I had the same problem with instructors at trade school
the older teacher was the more progressive,
the younger teacher was stuck on rule of thumb sizing, and
that heat pumps were crap.
sure was glad I had the older teacher.
20+ years ago heat pumps didn't work as well as they do
now. some teachers/techs/hvac company owners are still
convinced that heat pumps don't work. their loss...but
you'll learn differently.
best of luck.
The cure of the part should not be attempted without the cure of the whole. ~Plato