This reports the highest Q-factor recorded for this OTU signal during the bin. Because this reading sits in the rolling window of completed 15-minute history bins for this OTU signal, tracking the best-case Q-factor alongside the minimum for this signal helps distinguish a link with a small, stable margin from one that swings widely, which behaves very differently under stress even at the same average. For example, a Q-factor swinging between a max of 11 dB and a min of 7 dB on this OTU signal within one bin indicates real instability, unlike a signal holding steady at 9 dB throughout, within that completed 15-minute window.