With the introduction of low loss fiber optic components such as LC/MPO cassettes, loss budgets (test limits) are becoming increasingly smaller. As a result, installers are finding out that previous methods and assumptions about fiber testing no longer hold true.
While the Telecommunications Industry Association (TIA) still allows 0.75 dB per connector, factory polished connectors are closer to 0.2 dB. So when testing to TIA limits, installers are afforded quite a bit of measurement uncertainty. In other words, their testing practices need to be reasonable but not perfect.