@VeryLuckyParent, you don’t need the same number of large classes to have students spend half their time in large classes.
Here’s a stylized example: Say that there is a school with a set curriculum where everyone in an entering class of 100 takes the same 20 classes the first 2 years.
The last 2 years, they take 20 classes which have 10 students each.
There would be 20 classes with 100 students and 200 classes with 10 students, so only roughly 9% of classes have >50 students, but everyone would have spent half their time in a large class.
In any case, the key differentiator to me isn’t so much the class size but the class format. Seminars, lectures, and other formats (case study, flipped classroom) are very different from each other. Some can only be a certain size, but, depending on the prof, a lecture with 10 may not feel all that different from a lecture with 300.