I'm not an HR person but I say play her silly game and ask your doctor to please write out the limited hours that he has in mind and then ask for a signature not a stamp. Usually, MDs will take your suggestion as to limited hours. If you think 5 hrs per day would be fine you can suggest that to your Dr. and if he/she agrees then all the better. Get the fax number of Ms. helpful's office so that the doctor can fax directly to her - cuts down on time delays of snail mail. Ask the doctor's office to pop a copy of what they fax to you in the mail for your records.

I wouldn't say a thing about "feeling safe". If the doctor says your cleared for partial work... then your cleared for partial work. End of story. You can say "I feel fine right now and I'm excited about getting back to work".. blah blah blah. Play her game.

What you have here is a burocratic person who doesn't realize that the H in HR means HUMAN. Now you know exactly where she is coming from. She is protecting and serving the company and not the employees - which I'm sorry to say is very common during recent years.

Good luck