This reports the highest received optical power sampled for this wavelength during the bin. Because this reading is a cumulative, non-resettable running figure tracked only from a single start reference rather than any fixed bin, an unusually high max here can indicate an amplifier gain spike or a transient reflection hitting the receiver, which over repeated occurrences can stress sensitive coherent optics. For example, a max of -6.0 dBm against a typical -12.5 dBm average on this OCh suggests a brief overdrive event worth cross-checking against any receiver-overload alarm logged at the same time, accumulated since this row's single start reference, with no periodic reset.