Except that you would need rather more KC-46As to the same work as a smaller number of KC-30s if you were intelligent enough to have realised that in the first place, instead of looking at aircraft numbers!
Beagle: You can make your arguments without insulting people.
The fuel burn issue is, frankly, bolleaux. It's like saying the RB211 in the TriStar had a higher fuel burn than in the 747, so was more expensive to operate......except that the 747 had one more engine! A mistake which one airline's beancounters allegedly made...
No, actually, it is not bolleaux. If the KC-30 is large enough to support a mission, sending a KC-46A on that mission would use more fuel.
Neither of us know the DOD assumptions about the missions profiles. But my guess is that they have a pretty good understanding of the typical USAF refueling mission profile.