Yes Floyd, that pretty much sums it up I recon.
I too have done a bit of IMCS mast testing and have noticed the same as you. Quite a few time the SDM 100% masts from the same factory were actually stiffer than the lower % ones and usually over what the specified IMCS claimed. For a lighter weight sailor like myself this was a problem. The 100% masts were noticeably thinner walled (as one would expect) and seemed much more susceptible to damage from mishandling and accidents. I was particularly concerned at the effects on durability concerning wear from cam rubbing and the boom clamp on an already very thin section.
The older I get, the better I was.