EXFO FastReporter 2 - Manual (Page 131)

Working with OTDR Files
Post Processing Software 121
Changing OTDR Settings
Setting Event Matching Tolerances
The OTDR Event Table is built by matching events from selected
measurements according to the tolerance. To be matched, the distance
between events from the different measurements must be within the
tolerance.
You can force the matching of two events or separate them by changing
the event matching tolerance accordingly. The tolerance is applied to all
operations related to the event table including apply reference as template
and macrobends.
Tolerance Tolerance