Maybe something about different measurement criteria.... so could be both.
FWIW, our Cummins C engines' "crankshaft power" ratings are 450
hp "according to ISO 3046 fuel stop power. Fuel 25°C (77°F)"... but 430
bhp "according to ISO 8665 fuel stop power. Fuel 40°C (104°F)" Our data plate read "Rated HP 450 (metric) at 2600 RPM"
-Chris