Again, the premise is that you're exercising professional judgement. If you can't let a project go until it's perfect to a standard far past what's called for, that is itself signal. Either way: if the project budgets 4 hours, it is on you as a professional to stop at 4 hours.
If you run an interview process where candidates who take 6-8 hours and claim to have taken 4 hours score highest, those are the candidates you will hire.
That's absurd thinking if putting in 6-8 hrs outta what everyone else is doing and what is needed to get you a job.
For all its flaws, part of the benefit of an interview is it's time bound and equal for everyone. Similar to a test.