Since the price is not an integer, this is not an “off-by-one” error. No? It was the common mistake of writing `>` when `>=` was intended.
I kind of agree with you, but then, since it would fit for integers, I can’t think of a better name and could live with some generalization of “off by one”. I’m not a mathematician but maybe something like “off by n; n -> lim 0”
EDIT: Or maybe “comparison error”. I like that the best. But calling it an off-by-one seems wrong, especially as what we usually mean by that is something more like not handling the last iteration of a loop correctly.
“I think you are off by equals here”