you can try to find 200th word on physical book page, I suspect on first tries you’ll get different answers. It’s not dumbness, with poem it’s rather complicated counting and reciting (and gesturing, if you use hands), and direct count while you are bored (as in with book), might make mind either skip words, or cycle numbers. We aren’t built for counting, fiddling with complicated math is simpler than doing direct and boring count