I support the Q/A time as I stated on my previous comment, so the professor stopping in the way, asking for questions and explaining them more in detail is for

I support the Q/A time as I stated on my previous comment, so the professor stopping in the way, asking for questions and explaining them more in detail is for sure net positive. Questions are little tradeoffs, if everyone starts asking a lot of questions, obviously it will result in less information delivered in limited time. This is very similar to no bug policy in software, if you enforce 0 bug policy, your development slows down to halt, thats why some stuff is always NOTFIX or low priority.