I'm also trying to use up pre-cut squares I have left from earlier plaid projects. Definitely forces the blocks to be a bit mixed up, which I like, and blends well with my lack of precision when putting the blocks together, as a couple didn't end up being the right size.
I think there may have been a correction done after I printed out the instructions that I didn't pay attention to (and I apparently can't read), so I've created slightly new blocks. I figure they will fit together (or not) when I get them all done, and if not, I'll just use a few fill strips or blocks.
The basket block is one example--I just sized it up to the next size and will trim off the extra when the time comes. And the block to its lower right is another example. They were supposed to be 3 of the little blocks, but since each ended up exactly 1/2 inch too small, I made a 4th and stitched them all together. I may eventually just create a few more blocks of my own. And note to self: Measure, READ, and check the math before you cut and sew them. Duh.
Hope you are staying warm--Happy Stitching & Happy President's Day!