It could be dumb luck, but I haven't worked at a company that had official hours in about 17 years. I've got used to working at companies where as long as you produce good work, show up to scheduled meetings, and don't outright embarrass your boss, you can come and go as you like.
In that case, there would be a generally expected hours. You would still have to allocate expected finish time based on how many hours you are expecting to work per day.