Is there a more fitting NPC to give you this perk? I mean, Sabrae just makes the most logical sense in my head.
There really isn't a 'perfect' NPC. I've been thinking Dr. Lessau. I know psionics is not his department, but
1. You're on Uveto at the end of the Ice Queen quest, making it a natural starting point.
2. He's the most likely to know how to get into contact with whatever department of SteeleTech does deal with this. (SteeleTech does produce a Staff, so it almost certainly does have a department for it.) Anno, too, I suppose. You can't be sure the player recruited her, though and she might not be working for SteeleTech anymore, depending.
As for the explanation...because it's installed in the brain and not the lower muscles?
Where do you think the Cybernetic Subprocessor is installed?
Or Sensory Dampener?