What good is 28+ Shield Penetration?

Simple question - perhaps a simple answer, I have one guess.

Why does any weapon module have a shield penetration value greater than 28 when the highest shield resist is 27? Does damage to the weapon module erode its penetration value?

There’s no difference once you’re over the value.

Presumably the stat range is there to allow leeway for future changes.

Thanks. Do you know what is degraded when a weapon module takes damage? I’ve seen weapon damage and fire interval mentioned - is that it?

Weapons visibly get severe cuts in reload rate with accumulated damage. Anything else would just be conjecture on my part.