C3 was specified as 100 Oktan per german testing method. Allied testing method was different and usually gives 96-97 octane rating.
Fuel composition was changed several times but AFAIR retained the 100 Oktan rating.
I would be interested to know of a possible use of fuel triangles with 96 instead of 100.
http://falkeeins.blogspot.de/2009/12...3n-weisse.html