The source MIB's description for this object ('Default 0. Coefficient used in custom path prioritization algorithm.') is boilerplate shared verbatim with several numeric coefficient objects and doesn't match its own true/false syntax. Based on its name, this flag controls whether 3DNS retires (excludes) RTT samples that measured exactly zero from the custom path-prioritization algorithm, since a zero reading is often a probe artifact rather than a genuine ultra-low latency; enabling it stops such readings from making a path look artificially fast.