Shine, MatthyJ's post jogged my memory. If they are GM metric calipers, some of them used a bias cut seal that retracted the piston further than a normal square cut one. The cars were equipped with a "fast take up" MC that had 2 chambers for the front brakes and moved more fluid for the initial take up. Supposed to cut brake friction for better fuel mileage. A normal MC won't move enough fluid to get the pistons out to the rotors properly. With your experience, you probably already knew that, but I thought I would bring it up. If CPP is getting calipers from an outside supplier, they may have gotten the high retraction seals by mistake. The metric calipers are available both ways.