I'm currently doing a HST routine, and was thinking about changing it to incorporate different exercises for each bodypart each workout. For example: for chest I would do Incline BP and Decline BP on Sunday, Bench Press and Flyes on Tuesday, and Chest Dips and Incline Flyes on Thursday. The reason for this is that I have very stubborn muscles in that if I target only a certain area, only that area will respond. Like when I bench, only the middle of my pecs respond while my upper and lower do not at all. Would this be a sensible change?