Jim you are right, advertised and actual are two different things. Let's say they have a lens that transmits 99.7%. Factor in the .3% over multiple lenses and you end up with 95%. Same thing with Nikon. One lens is 92% all of the lenses added up make it 88% on the Buckmark. All of them measure different ways. The only way to really keep them honest is to measure their lens ability and figure out what is lost from the front to back.
Some of them even measure light that can not be seen by the human eye to boost their numbers, let's say 130 nm. I don't know anything about scopes above 95%, that is out of my price range. Would imagine the top ones could do it. Sightron SIII glass is used in Leuopold vx-7, I have no idea about either. I wish the article I copied that from had Pentax. They use Burris glass. But I would like to know if the gameseeker is fullfield II glass.