It is helpful to remember there are two damage scales in MGT2. The personal scale as the regular rules. And the vehicle scale. If you are using one or the other it works as you would expect, a 4D weapon does 14 damage against armor. When you mix the two is where you add the x10 multiplier. Vehicle/starship weapons do horrific damage against people, and personal weapons have a /10 damage against vehicle armor.
I think I've got that in my head. But as far as I understand 'Destructive' weapons (aren't they all!?) this seems to be in general rather than for the scaling. (p.74 of MgT2 Core Rulebook). But I may be misunderstanding in that that short section is in the middle of personal combat so perhaps that's what it is implying. They're only 'Destructive' in this context. But that really isn't clear.
Thank you though.
tc