GSIH vs SSH

[Sinnister]

I recently made a post in the small stakes forum about the differences between SSH and GSIH starting hand requirements. In general SSH is a bit looser, probably due to the greater post flop advice. However, GSIH is tighter but way more aggressive preflop. It teaches that if a hand is worth playing, RERAISE. This includes hands like AJs and AQ suited even kq suited. I prefer to call with AQ suited and call with aj suited only against many opptsreraise if everyone is in maybe, but definately not everytime since its worth playing. Anyways, no one answered this post I made and since I had loaned my SSH book to a friend I was going off memory and just gave up. With SSH back in my hands I am very curious as to what the reasoning is behind this difference of preflop play and if it is sound advice in GSIH. After all this is coming from Ed Miller, who I am no one to argue with. I just seriously wonder why the big diff in strategy. Could it be GSIH deals with higher stakes play?