Agree with remove the boot. Using the boot as a guide should get you to the tabslot that most likely will work. Now move it to the next (in the direction that should move the pointer towards the middle of the range) tab slot. You only have two choices. If the next one is out the other way, and this one is barely in, then barely in is what I would go with. If you haven't got any positions left to move it to, then you likely used the wrong holes in the plate, and a R&R is needed.
EDIT: Actually since, it's in the range, I probably would not bother with the R&R if there wasn't another tab to go for. My FF17+ is barely (I can't recall how barely, but I would have thought the spacing between the two tab slots would have allowed me to dial it into the middle a lot more than it did) in the range at the proper setting for one of my pairs of boots, and barely out the other way at the next tab. (I switch between my race boots and my cold-weather comfy boots - BTW I thought the race boots were finally ok, but I discovered after skiing all day at the t-bar hill, that they still need some work ).
Edited by Ghost - 6/16/13 at 7:46am