This is what mine, done exactly to the instructions, looks like.
Waaaayy too loose. The instructions have you doing the square in the size half up from the hook you've used for the first two squares. Here they are lined up in comparison.
Way bigger. Side by Side it's not much, but imagine trying to sew these together!
There's been enough errors in this project to make me want to re-write each square, and I'm not the only one who feels this way.
So. I'm in the middle of working the square again, but in my 4.5mm hook, instead of the 5mm hook this was worked in. Let's see how it worked out.