esaProbeHistoryMaxOnewayR2PDelay is an unsigned 32-bit value that reports the highest recorded one-way delay, in microseconds, from the reflector back to the probe, for a completed interval that has already closed and been archived into the rolling history log. Because this figure isolates delay from the reflector back to the probe only, it lets a technician tell whether a latency problem is one-sided rather than assuming the whole round trip is equally at fault. For example, scanning this worst-case one-way delay from the reflector back to the probe across a week of archived bins lets the technician find the specific hour a transient spike occurred, long after the live dashboard has moved on to newer data.