Doctors

Can anyone tell me why doctors feel it's neccessary to have you come in for an office visit just to tell you that tests results were a little funky and they want you to repeat the test in 4 to 6 weeks?
In June, I went to a family doctor to request a follow up glucose test (to make sure the gestational diabetes went away after my daughter was born) and she ordered the normal test for someone my age as just part of a physical. The thyroid number came back funny, so she said to go back in 3 to 4 months, redo the one test, and we'd discuss the results.
I went for the test on Saturday and the nurse called saying the doctor wanted me to make an appointment. When I put a stink and mentioned that I had a baby and no back up child care, the doctor got on the phone. The thyroid number is still funny, but in the OTHER direction. It's not off by much and she doesn't want to treat it right now because the two tests have been off in opposite directions, but she wants me to redo the test and is mailing me the order. How hard is that?
I understand that doctors can't bill insurance companies for phone calls, but it seriously took less than 5 minutes of her time!!! Why should I waste an hour or more of my time for 5 minutes of news?