| Adrick |
As others have mentioned in most d20s game AC is how hard it is for you to be hurt/take a damaging hit. not necessarily how hard it is to just be hit. see the paintball example.
which is why most touch attacks in versions of d20 ignore armor and only account for dex and maybe a class defense bonus.
A ship with more armor is probably getting hit more often but not taking damage unless the hit finds a chink in the armor. thus the higher AC to hurt not necessarily just to hit.
the issue for the first poster is this makes the energy shielding not taking damage before hit/damage is determined really weird if you can't ignore it in your head.
armor deflecting shots (causing no hurt/hit) can't happen until after a shield bubble has been hit and lost some integrity. the shield bubble doesn't/shouldn't benefit from armor. So either shields should have their own AC until collapse or the ships should be easier to hit until shields drop and so forth. but that gets needlessly complicated pretty quick.
So for ease of use just say armor also includes some projectors energy lattices whatever you want that provide strengthening(ac) for the deflection of any overlapping shields. mysteriously always the same ac bonus as bare armor. whatever techno babel you want to close the conceptual gap in the rules.