To me this is really just vegas saying "we dont freaking know"

A lot of times it is called a trap line, but it is truly difficult IMO to gauge this line as if it is a close game it comes down to a lucky shot and how the fouling plays out.
For example look at the end of the St. Johns game(i know the line was 10) and the end of the Mavs game(i know the line was 5). Poor execution by one team and some shots and missed FT here and there and there will be a 3-6 point swing(which is what a 2.5 line comes down to).

Get what im saying here?