"What to expect this week" emails

I'm getting emails on "what your baby should be doing about now" and I've noticed that it seems babies around DS's week should be using their upper body more. But it seems like DS doesn't do much with his upper body. When I do tummy time with him he moves his lower body the whole time, but not so much his upper body. He has particularly good neck control according to most people who meet him and are around other babies his age, but he doesn't reach out for toys or push himself up on his forearms or anything like these emails are making me think he should. Are they just trying to make me paranoid? I know DS is an exceptionally bright child what can I say, I'm particular, but between him not smiling very much usually just when he first wakes up and not showing more interest in the stuff around him, I'm starting to wonder.