I'm a bit confused after 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bf5 5. Nc3 e6 6. Nh4 Bg6 where Avrukh recommends 7. Be2. It seems to lose a tempo if Black plays dxc4 and allows Black to choose such tactics when they suit him. Secondly, g3 is sometimes a necessary move in these lines. Thus, Be2 appears committal because the bishop might want the long diagonal (but it does look like a pretty terrible diagonal at the moment). I can understand that White may not want to take on g6 because the bishop isn't going anywhere and the pressure on the h-file can be unpleasant, but why not start with other moves like Bd2 or Qb3. With a knight on c3, the dark squared bishop is unlikely to go to b2 and the attack on the b-pawn is always a bit annoying. Basically, I can't understand why Be2 is preferred. However, plenty of strong players favor Be2 so I'm sure it has some important advantages. Although, the only one I can find is that White gets to castle faster. On the other hand, shouldn't White delay castling until Black commits? After all, if White castles too early, Nxg6 is ineffective because Black just gets a lot of pressure against his king. Please help me.  

Note: I think I've figured it out. It seems that Be2, allowing Black to "win" a tempo with dxc4 is always going to be an issue. Whether White starts with Bd2 or Qb3, he will eventually play the light squared bishop out to e2 so Black really doesn't gain any new options if White starts with Be2. Moreover, dxc4 seems to open the position for White's future bishop pair and isn't recommended too early. Hence, Be2 may in fact be the most flexible move. Although I'm still not sure because in the 7. Nxg6 lines White doesn't hurry to play Be2 (but he's no longer planning on K-side castling so it's understandable for other reasons).

BTW: Whether the repertoire is suitable or not for the majority of players under 2000, it will still help you understand chess better just going through it. In any case, the fact that Avrukh takes a serious approach and tries to find the truth in the position with plenty of deep analysis is precisely what makes this book special. If it were meant for 1500s, I probably wouldn't have been interested in it in the first place.