Hello,
Thanks for information.
I think the difference of Roots or Tween screw type is compression method.
It is same that these have two rotating shaft combined with bearing and gear connected with one snout shaft which needs lubrication.
My point is that as Mobil jet oil melts plastic, it will affect rubber seal or break any tightness with longtime use.

Is here someone who expain why jet oil melts thin plastic cup?? Normal engine oil will not.