There is no rule breaking going on here. Where I've been handed a formal policy document at a tech employer, it's always said something along the lines of "Hou

There is no rule breaking going on here. Where I've been handed a formal policy document at a tech employer, it's always said something along the lines of "Hours are X to Y or as your manager directs". The latter part of that means in effect "this is between you and your manager unless you can't work it out". If you can't work it out, best to go elsewhere, because that's a toxic culture for a tech company.