Hello Margs in America when it comes to sinemet allot of times some doctors look at your age and if your symptoms are mild. If a person is younger the doctors sometimes us drugs that target the cells that make dopamine. I am no doctor. But the medicine cause those cells to produce more.
Getting back to the amount of pills and timing when to take seem to be trial and error. I started with 1 pill of 100/25 sinemet 3 times a day at 59 years of age. It is hard to get an appointment and the wait time can be 6months here.(USA) What was suggested to me by other will PD was to keep a daily diary.I wrote down from morning a to night and how I slept all my symptoms and their severity. The doctor could get a very good idea on adjustments of medicine given. Through time I have increased over 5 years to 2 pills every 4 1/2 hours and 1 100/25 slow time release sinemet. (total 900 ml. per day)
If you are under medicated you will get slightly worse. (the disease is progressive). The reason I say to keep a diary is because we are all different. (Protein intake effects,Slow GI motility, Activity level,injuries that we have had that might effect the symptoms, depression, anxiety, tiredness, and so on).
So with all this above,with such a short appointment time (15 min. USA). Then add in the long time between appointments.
I hope the daily diary and if you have lost faith in your doctor. Find a new doctor if possible. your doctor should be impressed with the clarity of the statice of your disease. Hope this helps.