I said nothing about hard to kill. Moose are hard on bullets. The majority of moose I've killed have stopped bullets; everything including Core-lokts, Hot-Cors, GameKings, Partitions, FailSafes, Ballistic Tips, XFBs, Uni-Cors, Grand Slams, TSXs, Weldcores, Interlocks, A-Frames… I have them. Doesn't matter whether they are shot with 6.5x55, 7mm-08, 30-30, 30-06, 340 Wtby, 358 Norma, 375, 45-70, moose don't have any trouble stopping stuff. The 139 Interlock is an ideal caribou bullet in the 7mm-08. Perhaps it's fine for elk; I can't say one way or another. I certainly wouldn't suggest it as a good choice for hunting moose. Monos have lost their luster with me as well, but the TTSX is easily the better choice of the two the OP inquires about. I think the tip has certainly helped it overcome the most serious problems it previously had sometimes.
I think your point about "hard on bullets, not hard to kill" is a good one and agree, I'd rather use the TTSX over the 139 Hdy.
But he also asked about the Partition or Accubond, and those are what I'd use (and do use) over either the Barnes or Hdy. And I can't imagine whatever works well for elk wouldn't work similarly on mooose.
