I had a new key cut and it seems that it's juuuust a bit "off" - it works fine in one orientation (both in the doors and in the ignition) but if you flip it over, it won't turn - easily, anyway. You can wiggle it around and gently put a little pull on it and it MIGHT turn.

I had a door lock cylinder out at the time and noticed that it doesn't quite suck in the wafers to the point where they are flush with the cylinder. Does this mean the key was cut too far/deep or not far enough?

I'm wondering if a little gentle overall filing/smoothing might help but not sure which side to do since it turns one way, but not the other...

Try buffing it with a wire wheel.

The answer to your question.... it depends. Take the lock cylinder out and with the key in, try to find the tab which is not fully retracted.

The tabs are pulled down into the cylinder by the key. Some from one side, some from the other. If a tab gets pulled in too far and sticks out the back, the opposing side of the key is too high and could be filed down. If the tab doesn't get pulled down enough, the key has been filed too much and can't be fixed. You'd have to file down the top of the tab, or take it out entirely.

Ahhh - ok. That's interesting. I had the driver's cylinder out and put the new key in and could see that the tabs weren't quite getting smooth with the outer surface of the cylinder - but I didn't know if they were pushed or pulled. I will investigate further with this new info.

It's actually interesting - and maybe a sort of an anti-theft device - trick key!