Though it's more of average. Some weeks will be heavier than others, but I try to assign four hours of work outside the class oer week on my syllabus.

That’s probably the way things should work, but it’s just not what really happens in my experience. I have never once been part of a syllabus discussion in which the concept of two hours even came up. My sense is that most folks assign an amount necessary to achieve their learning objectives with some eye towards not overloading students but no specific thought to what it translates to in time.

I’m guessing there must be student survey data on this and I’d be curious to see what it shows. I certainly spent nowhere near two hour per credit on studying in the aggregate while at ND.

How much ground can I cover in 36 hours of lectures and 72 hours of outside of class time?

It is even more important if you've tried to flip a classroom.