I Take Ranexa - 250 Mg In The A.m. And

I take Ranexa - 250 mg in the a.m. and 500 mg in the p.m. My Cardiologist has me on 20 mg of Simvastatin. He told me to up it to 40 mg in August. I didn't do this. I had more blood work done and my cholesterol levels came down but he still wants me on 40 mg. Then he tells me two months later that I shouldn't take 40 mg while on Ranexa and should switch my medication so some other statin. What is going on?