Three checks, in increasing order of what they catch: every event against its own limit, the whole link against its computed budget, and the measured end-to-end loss against the sum of its parts. The third is the one no threshold test finds — when the two numbers disagree, one of the documents is wrong, and that is a different problem from work that is out of spec.
Your test results
Export the report from your test suite rather than the raw trace. A .sor is the OTDR’s own binary and this does not read it — guessing at a proprietary format would produce a validator that silently checks the wrong numbers, which is worse than none.
Columns are matched by name, so EXFO, Viavi and AFL exports all land without editing: a link or span id, its length, wavelength, end-to-end loss and return loss, plus each event’s type, distance and loss. Kilometres and feet are converted when the heading says so.