I've never actually seen anyone ask this question before so I don't know whether or not it's been asked/answered before.
Does ammo which has -DT have a cumulative effect on a target with repeated shots?
For example, let's say i'm using a laser rifle with optimized ammo(-5dt) and it does 20 damage. If I attack a super mutant (who has 15DT) multiple times, does his DT drop with each hit until it reaches 0? Or does it stay at 10 DT for each shot?