Ah, that does make more sense. Yes, that is rather different from the tabletop. Not that a Land Raider can't bounce a multi-melta occasionaly there, but being immune is something else.
This is making me wonder if the the Dark Angels psychic power that grants armour might be getting a nerf. Even a starting character who pushes can get to +18 armour and no penetration, for an effective armour of 26 + toughness bonus. Since weapons lose their penetration that's practically dreadnought level right there.