Mr Selfish
You are spot on.
Since the R22 HP model took the power to 160 HP from 150 HP the weight was kept at 1300 lbs. Aim was to get better high altitude performance, not to overboost or go out too heavy.
As there was a need to carry a bit more, the Alpha went to 1370 lbs. Limit was still 124 HP.
The limit since the Beta was introduced has always been 131 HP for takeoff - limit five minutes.
Then max cruise using 124 HP.
The bigger 180 HP engine was to provide even better high altitude performance. The power falls away as you climb up to a mountain top.
It is a derated engine by RPM and MAP. The placard says it all!
I was watching that now famous NZ video on the R22 and noted the powere settings recorded by the camera. Bit scary I thought.
All we have to do is keep within the limits.
The old farts who say "if it can hover" it is OK. Do they really understand that metal has memory?
One industry icon recently told me that he gets going by turning off the governor, overspeeding the rotor, overboosting MAP as it struggles through TL, then governor back on.
When asked how heavy he was - with two big guys, full fuel, a rifle, ammo, seats full, etc.
His answer said it all: "Dunno"