Folk need to be wary of foreign POH data. Generally we are operating from non-critical lengths and it is very easy to fall into the trap of convincing yourself that it is all fine and OK.
Reality is that, for a critically limiting takeoff .. it just might NOT be all OK.
The old style DCA flight manual P charts (a few of which I drew up) were a reasonable balance of being not too optimistic and not too conservative.
You use the foreign POH with uncritical consideration at your peril in the case of critical distance takeoff.
Also 1:15 is not 15% according to my calculator
Allowing for the typo, if 1.15 isn't a 15% pad, what is it ?