flightlessbirds

I believe it is when your starting position (ie MKE-CRJ-RC) is shrinking and requires some displacements. If you bid and get something else that you’d rather have, you have preferenced to displace out of that shrinking position. Thus it reduces the over-staffed-ness of that particular position.

vs an award which is just filling a vacant slot. Don’t quote me for certain though.