"There is NO printed data stating we have a 10% fudge factor in converting long tons to PSI."

Really? This is from a web page you referenced earlier in this thread -

"In Britain, a third set of crusher standards were developed, using a "base" crusher. . . The units were generally stated in Britishicon long tons per square inch, or tsi. Pressures indicated by this method run 10 to 20% below those indicated by radial crushers."

I'm afraid you've gotten confused between Winchester ammunition (including cases) and Winchester powder. Same name - but different products, manufacturers, corporate affiliations, and marketing/distribution channels.