Take a look at all the games this season for my two DT's, i havent even taken the attributes for pass deflections up all the way yet, im still working on them... They are starting to produce PD wise and it definately adds an element to thier game that you dont normally get from a DT.
40 jumping on my DT with a few VA's in Towering Man this season and it seems to have slightly increased my PD's. They do say a PD is almost as good as a sack so if you get 1 or 2 in a competitive game then it may not be a bad investment end build.