I see your point. I am sure that my views are heavily influenced by my experience which was good. I know that I was not supposed to work over 20 hours per week. It did not matter if that was all research or a combination of research and teaching a class. At those hours I was a part-time employee so there was not need for the university to extend any benefits to me. I also made sure that I only worked 20 hours a week. I did not feel any pressure to put in more hours than that.

My wife is currently working on a PhD and she is also only expected to work 20 hours a week. It is very much about the individual program and the department/field.

Wow, I've literally never heard of a PhD where you were only expected to work 20 hours/week. I'd say 50-60 is closer to the norm, especially once you're done with your coursework (usually a year or two into a 5-7 year long PhD).

If you don't mind, what field(s) are you two in?

I can only make sense of what he meant assuming it is 20h/week on top of the "study time" purely for the purpose of the PhD. But then that seems like a lot, I wonder what's in the 20h...

Yes, 20 hours of research time. Her studying time/course load is all on her own time.

In some countries (most universities in France AFAIK for example), "research time" is all of what makes your PhD. You don't have any course (it is changing a little, but seems quite superficially though).

That's because you're required to have a Master's to start a PhD in France, whereas in the US you get into a PhD program right after undergrad. So in the US, you end up taking some classes your first year or two, then you typically take the qualification exam, and then you start writing your dissertation.

I only get PAID for working 20 hours/week.

I am a traffic engineer and she is a hydraulics engineer. Both fields fall under Civil Engineering. Her degree is only a 3 year program (she already has a master's).