Well in terms of synthetic equivalents, if you consider that the version of the Halo with baffles similar to those on the UL shirt – and almost twice the down fill – tested as roughly == the cocoon 60 then its clear the UL shirt can't be very warm.
In fact in terms of insulation at this weight point it very likely loses rather badly to something like PHDs ultra/WM's flight vest. Certainly an awful lot more core warmth, if of course less on the arms :)
Suspect implementation was reasonable, but they just pushed the basic design idea a bit further than it really rationally goes.