HR determines the upper and lower range of the salary for positions. It’s actually in your boss’ best interest that you’re brought on at the highest in that range so that you’re the happiest you can be in the role.

So you’re really just negotiating with a third party (HR) that you’ll never talk to again in your day to day.

Maybe someone else can speak to HR incentives though. Are they incentivized to low ball you? Not sure. Either way, it’s just business.