This situation actually has nothing to do with your practicing. Our common sense of abdominal muscle compartmentalization is actually the wrong concept. What we call abdominal muscles are the rectus abdominis. There are only two rectus abdominis muscles on the left and right sides of the body. The reason why they are "compartmentalized" is because each one of them has several "tendon rows" (the horizontal lines you see in the image) that divide the rectus abdominis into several muscle bellies. However, these tendons are genetically determined and cannot be changed. Many bodybuilders have this condition, and if they could change it externally, would they leave it alone?