I have a lot of hands-on-experience with PPC, and I know how to control and manage the CTR, CVR, CPC, ACOS, and TCOS, among other things utilizing PPC. Because the PPC is science.
There are numerous factors that contribute to successful PPC with ACOS under control. Optimized listing is the first and most important factor. With very low ACOS, your PPC Campaign will be more successful if your listing is well optimized.