All in all pretty good job! I can see a great deal of improvement over the set.

First thing I notice though is that you haven't been drawing shallow perspective boxes. These are boxes that have their vanishing points very far away from the page, and are in general more common in drawing that the extreme perspective boxes, the ones have been doing are.

So I recommend you to practice on your next warmups shallow perspective boxes, as they are pretty important.

I notice that you still have a few issues through the challenge with the inner corner. Making the boxes on this order helped me a lot with it. Hope it helps too.