As long as the holders are mounted centrally, it's not the steel, it's the boot. It's a newer, stiffer boot that I assume is fitting you better than your older boot. This better fit helps to hold the ankle straighter therefore you have more edge biting into the ice. Your older boot has less support for the ankle, this allows the ankle to fold slightly inwards on the outside edge (the boot stands more upright) and therefore the edge isn't as good. If you are noticing this big a difference between the 2 boots on an outside edge then your bio mechanical alignment (ie pronation) over the skate blade isn't that good.