(First, I don't know if it's voluntary, but 1 page doesn't mean 1 sheet of paper, but only 1 side. However, doing these exercises twice can't hurt you)

You seems to struggle with the superimposed lines. Try to make way smaller lines, and then increase the size step by step. You're fraying to much at the end ; in fact, that's not such a big deal, but don't make the task too much harder, otherwise you won't progress.

Nice ghosted lines, try to practice smaller ones too.

Good ghosted plans, don't have much to say about.

Table of ellipses: since you've done it 4 times, we can see the progress. At first your ellipses didn't fit in the cases, but you've correct this mistake.

Plotted perspective is good.

Rough perspective: really good, your freehand lines will get better with experiment.

Great rotated boxes, the result is really nice on both drawings.

Organic perspective: be sure to keep your boxes on the line, and rotate them a little bit more, but that's good. Your boxes aren't perfect, so the 250 boxes challenge will help you improve a lot.