This is the dampening interval for a custom per-user/group falling threshold, defaulting to a resource-owner-sub-type-specific value if the falling threshold itself was configured but this interval was left blank. As with the rising-side interval, this default-inheritance behavior means an admin cannot assume an unconfigured falling interval equals no delay -- it equals whatever the sub-type's standard dampening happens to be. A custom falling threshold set on a resource group without an explicit falling interval would use the same default dampening time that governs every other consumer of that resource sub-type, rather than a group-specific tuning.