Here is some interesting stuff --
http://www.footballoutsiders.com/stats/dl
This second table lists each team's Adjusted Line Yards in each direction listed in official NFL play-by-play, along with rank among the 32 teams. Only five directions are listed because research so far shows no statistically significant difference between how well a team performs on runs listed middle, left guard, and right guard. These runs are from the perspective of the OFFENSE, so a run listed as LEFT TACKLE is actually at the RIGHT defensive end.
If I am reading all this correctly (which is never a given) then the Steelers are far worse per carry to Watt's side than Dupree's side? Interesting stat if I have that right.
Also, it is possible that we are looking at an Artie Burns factor here also? Doesn't he usually play behind Watt? IF you look at all the stats in the linked article, it is pretty clear that the 2017 Steelers do not field a good run defense and it seems like tackling at the DB level is one of the primary problems.