I would take all of these kinds of analyses with a grain of salt, so to speak.
(egh...yeah, bad pun...)
A lot of the differences in those ratios seem pretty meaningless when you look at the amounts they are actually picking up. And, as has been pointed out, their methodology in preparation, testing, and reporting is suspect.
I won't believe any salt analysis until I see one that is done *independently* and with a more rigorous methodology.
(I read the thread on reefcentral a while ago, and a couple of people came to the defense of the testing methodology...including someone associated with the testing, IIRC. It just doesn't quite fly with me).