The book for my 03 says not to use the LATCH hold downs in the middle of a Quad Cab back seat, but the book for the seat says any latch hooks at least 11" apart are ok. I wonder if the reason the truck's book says not to use them is they would interfere with the seat belt latches for the outboard seats?
I'm eating dinner in my truck reading this thread on TDR so I decided to take this picture. View attachment 100187
I have the tape at the center of the passenger side inside latch point. There is roughly 27" between those latch points. And you are correct, it would extend the lower anchor points 3" inside the outside seat belt latch.
As you can see from the picture, I have a rear facing child seat in the center of mine mounted with the seat belt.