Many years ago Gidon there was a programme on the steam radio called 'Around the Horn' and they used to come up with such pearls as, 'are exits on the way out?' or 'how much is a four penny loaf'.
Believe me, the way some things are measured these days is about the same.
To have accurate figures you need to know how the measurements are taken, and that is very rarely specified.
The orientals don't use the same horse power that we do, neither do the yanks, so without knowing the standard used you can't even make comparisons.
So 'when is a horse power not a horse power?'
I'm off back to my cuppa!