I am a beginer, I have been doing HCT-12 for a month now and have gotten great results so far. (great results for what I have ever experienced before on other programs I have tried)

I have two questions that could alter my main question.
1. Is not feeling sore a sign that you are not working the muscle hard enough?
2. Do some muscle groups require more reps than others (have heard that for legs, abs, forearms and shoulders more reps can give better results)

Main Question: I feel like I am getting really good work outs following the 4-5 sets of 6 with a cluster set at the end for Vertical Pulling, Horizontal pressing/pushing, Triceps, biceps and Hip dominant. However my Vertical pressing (shoulders to be specific), Calfs, and Abdominal exercises dont usually make me sore and my quads are also never as sore as my hamstrings. I know that in the program it explains calfs should be worked out a little different as far as the negatives go. My question is should I be working out my shoulders, calfs, quads and core differently? more reps? more than just one exercise?