I mean many teams didn't even use it last year.. Take a look at last years trade:
http://espn.go.com/nfl/draft2012/story/_/id/7854788/trade-tracker
then compare it to the value chart http://www.draftcountdown.com/features/Value-Chart.php
Many are about 50pts shy or short.
Here's an example of one:
Green Bay Packers: Acquire pick No. 62 in 2012
New England Patriots: Acquire picks No. 90 and No. 163 in 2012
GB 284
NE 122 and 26.2 Over 100 points short of equivalent value. Well now I ask, what's the point of the value chart if many teams don't even use it?