When you're an employee, you're paid for the time you spend at work. The productivity is not part of the equation in the contract.

Technically for a salaried "professional" job your not normally on hourly pay.

I ask every time and most jobs will tell you that they expect a 40 hour week on salary, if we want to be minute per minute pedantic I'm leaving at 10am every Friday.

That presumes there is something work-related that needed to be done during that time.

If you’re meeting your expectations, taking a 10 minute break to take a shit at work doesn’t mean you need to work 10 minutes at home.

HN is research time. Perfectly billable.