Neil's summary is right on the nail. I spoke to a major line manufacturer recently about this very thing. They said that the raw material had a strenght tolerance of +_ 10% meaning their finished line could be +_ 10%. There could be no consistancy in line strenght and and that IGFA rated lines would be too hard to guarantee. The declared strenght on their braid spools was a MINIMUM, meaning it broke up to 10% above.
Can't really comment on FINS or YGK braids that mention IGFA, you are best to test the lines on the Club'r IGFA approved scales before you fish the tournaments.
The upcoming Tutukaka Kingfish Tournament held in June, had a jig-only section where braided lines with a max nominal strenght of 50lb is permitted -and encouraged! This will be the first known NZ tournament that has a braid permitted section. Quite a concession for a normally IGFA bastion.
