Sure, I just didn't want to go as deep as different slicings of spacetime and comparing position-dependent dynamical quantities on a slice of scri+ with quantit

Sure, I just didn't want to go as deep as different slicings of spacetime and comparing position-dependent dynamical quantities on a slice of scri+ with quantities on a spacelike slice that you expect to always appear in the same form somewhere in every successor slice. On that last point, the latter (ADM) always stays the same, doesn't it? In early spacelike slices when the binary system is radiating basically nothing, the quantities you will find in the GWs in later slices are just clustered around the black holes. Mass in General Relativity will give anyone a headache; I was trying to side-step that without being caught shuffling gravitational radiation off to the source side using pseudotensors. :-)