calibration and dyno type....
same dyno type but different calibration will result in different reading of the same car (not taking weather factor into account yet)
different dyno type will of course result in different reading too..
then there is also the conversion of the measurement count too...
to understand u need to know what type of dyno u are going on... load dyno or inertia dyno...
and then u need to do the ambience temperature correction too to compensate for the difference in air humidity/bla bla bla....
bla bla bla bla bla...
(damn i hate spoon feeding... like how this
fella tembak ppl for being spoonfed

)
even i also mind-fucuked at this thing at first but i learn slowly....
giving out direct % numbers is just plain... oh well....
leave it to the floor to decide which is a better explanation...
P/S:
aku budak baru belajar, kalau salah tolong tunjukkan ya...

what this kacang really rajin till can embed link in his comment huhuhu..not your average troller.