Clomid question!

My husband and I have been trying to conceive for two years. Everything is ok with me. He has low sperm morphology. This cycle we are doing <a href="https://glowing.com/glow-fertility-program">iui</a>. My doctor has put me on 100 mg of clomid. To give more targets for the sperm I guess? Does anyone know why some doctors prescribe 3 to 7 and some prescribe 5 to 9?