The game only talks about things in the parentheses being affected by TA or MA. It never said anything about other items as well. As you sure base stats are also affected by the TA/MA meter? I have never seen anything like that even mentioned in the forums and other places I went to to look for answers.
But then you gotta ask yourself, what's the point of the Aptitudes, anyway? I'm not entirely sure, but seeing how things worked out in the game, I think it's safe to assume nearly everything related to combat abilities are affected by your aptitudes. And if you dig deep enough in Arcanum forum, I'm sure you'll find something related to this topic. They're rather old site, though, so maybe that's why it's kinda difficult to find the answers. If only Drog is still here...
However, if tech items have a hard time hitting magic beings, then a tech guy is really in deep frikking doo-doo if he goes all out tech. Mages, on the other hand, will just Jolt or Lightning Bolt tech creatures to death. Seems a bit odd.
How did you come to this conclusion? If tech equipment have a hard time hitting magic beings, shouldn't the same logic applies to magic hitting tech beings as well? Especially since my tech-char actually need to recast Necromantic White spells upon him multiple times by Virgil until it could actually heal me. Do remember that the game has critical failure mechanics, means if you try casting magic upon, say, an Automaton, it might fail to cast and nothing happen; or it critically fail and something horrible happen to your character instead.