"Interpretations" can creep in through the narrowest of cracks, I find, and once you realize that your using a few juicy "interpretations," well, it just gets easier to do from there.
But, honestly, I think that was the original intent of E.G.G. It was only later on that he started to throw around goofy words like "Official Dungeons & Dragons." The 1E DMG as much as explicitly says that DMs can and should adapt and change the rules to suit their own games and worlds. To quote the master, "Know the game systems and you will know how and when to take upon yourself the ultimate power.....[The players] are playing the game the way you their DM, imagines and creates it." Dungeon Masters Guide, E. Gary Gygax, TSR Games, 1979, p. 9.