I am asking this because I was just looking for IEC 62366:2007. Looking at the usual locations like ISO store, Techstreet, BSI & Web store where the standard runs between $200-$300. I found other locations which have the standard as AAMI for $30-$120. Why is the AAMI version so much less? Is this not an official version? Also, what makes the standard an offical version? Is there some "check sum"/word count so I can verify nothing is missing if I buy it from "Bob's Standards Store" or an ANSI/AAMI/IEC version?