I disagree that -2LV is "enough", though.
I think we agree this is not about agreement, but just about if some shooting styles requires it or not...
If I understand it correctly, -2LV means @f2.8 (the fastest speed you'd expect the af to work flawlessly and not require mf tricks) and iso12800 (arguably the fastest speed that makes a residual sense) ... 1/4s. Personally, I'm unlikely to shoot with 1/4s handheld requiring phase af, let alone 1/2s of -3LV.
The one situation where -3LV might make sense for me is with a IS prime which axes up to 4 stops from non-IS handheld, and @24mm you just might be able to handhold 1/2s if you've got low blood pressure... but I don't have such a lens, so it's not necessary for me, I'm more interested in *fast* phase af at lower light levels.