RE: Changes?
By weight or by volume. John, many modelers have asked the question. My fuel company as well as most others measure by volume. At least one company I know of measures by weight. Your numbers are a little off but the idea is correct: equal percentages of nitro, measured by weight and by volume where the remaining components are fuel ingredients, the one measured by volume will contain more nitro than the one measured by weight. Keep in mind that the company I know of does disclose their measurement method and are hiding absolutly nothing, you are getting exactly what they are telling you, its just measured by weight rather than volume. No industry standard exists and it is up to the company making the fuel to determine the method that best suits them.
It is my professional opinion that the percentages of oil, nitro and methanol were determined by volume by the founding fathers of glow engines. I don't believe that any of them weighed out the fuel components on lab scales when they were experimenting on the best percentages of fuel components when trying to make an engine run the best. Reality tells me that the founding fathers of glow had an old jug of some sort and a couple "borrowed" measuring cups from the kitchen. They made fuel, based on volumetric measurement and thats where it all started.