That sounds like an issue of comfort more than concealment. The G27 is a G22 with a whole bunch of material chopped off both ends. It stands to reason that it will conceal better on anyone except those born with a G22-sized alcove somewhere on their body. Claiming the contrary is a little bit like saying that a Lincoln Town Car limo is easier to hide than a 4-door Town Car.
For context, the G22 and G27 have been my EDC pistols at different times, for several years each.