Clocking in the tunnel means that the extractor has room once installed to rotate a little: If the hook typically points at due 9 o'clock in the gun, imagine it having enough wiggle to rotate between 8 and 10. The result is inconsistent tension and engagement with the case rim. The fix is a fitted fps that holds the extractor more precisely/firmly in the rear.
I've been wondering the same thing about the force necessary to pull the extractor; pushing the hook over to pull it and popping it back in might eat up a little tension each time. If this ends up being a thing, filing that tab down a should solve it as it'll give the whole unit a little more room to hook-in while installed (and being taken in and out)