All I want to know is: why do I have to work as many (unpaid) hours as necessary to get the job done, but I have to count the hours I take off?
If the employer values you they will either tell you not to work more than the 40, or tell you when you can -- shifting the power to you.
There is no rule -- or should there be, about negotiating such terms.
Switching back, I think this should arrive more from our culture as it takes an assertive individual to do this as of now. I am a little hesitant to make such terms gov't mandated -- but I would like to hear arguments for it.