High calcium levels (hypercalcaemia) can cause hyperparathyroid (over production of parathyroid hormones).
When the adrenal glands do not work well and produce few adrenal hormones, it can cause hypoparathyroid (low parathyroid hormone production).
Your high levels are probably from the Graves disease. Few things are high with Addison's disease. I run on low.
You might want to discuss this with your doctor.