You say your goal is to gain muscle mass and definition, I was wondering if you were using light weights and high reps to do this at the same time? Personally, I would never use a high rep workout to build muscle, and I believe that high reps to increase definition is just a myth. You can do 4 sets of 20 reps with a light weight and get a nice pump to your muscles, which will result in a large but temporary increase in muscle size, but wait a day or so and you'll notice you might have even lost some size do to all the calories you burned. In the mass building phase I use between 6-8 reps, but with the high weight I use it might take 45 secs for me to finish a set.
Muscle definition has to do with body fat% and water, not how many reps you did. This is why you focus on gaining mass first, then you can cut back on your calories and burn some of the fat. And if you really want to track your progress, remember your weight before you started gaining mass and compare it to your weight after you finished cutting down. If you gain 40 pounds of mass and then cut down 20, you gained about 20 pounds of lean muscle. Remember also that you probably won't get the definition of a pro bodybuilder, they cut down to about 3% BF and dehydrate to look like that.