In my experience there are only two estimates that consistently matter: "really really easy" and "really really hard." If your Product Manager thinks a task is easy but it's actually hard, you have to teach them so they can decide if it's really worth the effort right now (or at all). If they think a task is hard but it's actually easy, you have to teach them so they can decide if it should be prioritized for a quick win.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.