Not exactly as above, because, if a weapon did ZERO damage ignoring armour, it wouldn’t get applied a second time and so would still just do 60 damage. If 10% of its 60 damage ignored armour, and the target hit had 60 armour, then the armour would be destroyed and 6 hit points would be taken.
Hmm… are you sure about that?
If you had a weapon with 50% ignores armor, that dealt 60 damage, and the opponent had 60 armor – how much damage would you deal?