Late reply.... but
some research here:
https://mglbaseball.com/2013/12/09/p...ties-revisited
which suggests that a player becomes 5% less effective at the plate when they are a DH in real life, than when they are out in the field.
So you are very observant, and it is likely that the game engine includes this, given Markus's affinity for SABRmetrics.