Ben sounds about Par for course. Same as my first and my buddies vangs.
Advantage to port is less rise and faster secondary target accusition (keeps the sight picture clean). Would do it again in a NYM, but then again I envision targets out to 50yards and all the pellets on. Have seen this done with vang comp, have not seen it done by factory remington with whatever choke choice or combo.
Many PD'S have had their guns done by vang so someone incharge of that decision must have thought it helpfull. Maybe keeping all the pellets on the BG if possible instead of having them flying past BG and into who knows what.