Being a PMR sufferer it is common for your cortisone to be in normal range. It is very difficult to have an accurate test while taking any amount of prednisone. So Dr. wont even bother, Most of the time an endocrinologist will require that you are less than 3mg day then testing is done at least 24hrs after your last dose. But even this testing is suspect whether its accurate. My guess is you are correct though. Adrenals are still trying to restart.