Let me back up a little.
When I was in grade seven, my mom bought me a pair of size eight runners so that I could grow into them. I never did. I remained size 7, and wore out those too big shoes. In fact, sometimes 6.5 worked just fine.
Anyway, when the salesperson asked what size I wore, I said 7. She suggested that she measure me, which she did. She came up with normal width, size 7.5.
Oddly, that's what happened last summer when I bought shoes for work, so when I ended up with 7.5s again, I actually started to wonder whether shoe companies had randomly changed their sizes.
And then I came home and put the new shoes beside the old ones. They are noticeably bigger.
I don't understand why they both fit.