This makes sense. All of the original NSX techs from Acura were trained either in Japan or at one of the US training centers in the early-mid 90's. They were specifically taught to leave the engine in and do it that way. In Japan, most of the NSX specialist techs migrated to dropping the engine because they discovered that access was far easier. Both the Refresh Center and T3TEC drop the engine for the service (but leave it in the subframe). Kaz and LarryB do too. So do I.
Having done it both ways, there's no way I would ever do it "engine-in" again. YMMV