Your argument is specious because the ASTM cert (if it exists) does not compare it to the brands available at hardware stores.
Why would I assume your figures are accurate? (I already told you I don't trust what salesmen tell me, unless verified by independent objective third-party proof.)
I bought 3M epoxy resin and hardener at Lowes. It appears the same product is rebranded by West Marine as their epoxy.
I don't believe there is any difference, other than the price and the pump, unless you prove otherwise.
ASTM is a 3rd party testing lab, and testing protocol book that does exacally what you are asking for. Assuming West Systems has the cert (they do btw) then there is a third party lab that has verified the numbers they claim are in fact what was measured.
If you want more third party than this I don't know what to tell you. The hardware brand in the same physical property test has numbers about 1/5 what West Systems does. Now they may be lying about their product, and I don't think they have it tested, but I also highly doubt they are going to lie about it to make it look worse than it is.
3M is a while different story. They make a huge variety of different resins depending on application. Heck they have two different resins just for pultruding, let alone thier infusion resins, adhesive resins, bagging resins, baking resins, low temprature resins, underwater resins, ect... I haven't counted but that likely have 40 or 50 different resins for different specific applications. They may all be similar, but they are not all the same.