MPL,

Its normal for the passages to stay full but I would think it takes a while for the oil to run back from the valve area above the head. But not 4 quarts, maybe one quart and even less if the engine was hot. I always prefer to check my oil level on a cold engine.

Your son had the right idea of checking oil and adding some. You just have to teach him to be a little more patient and check the oil after he as has added some.

P E H