This is resolved in the r3.6.5 February 2019 Update Kit or the PM r3.7 GA release.
Install or upgrade one of those releases when available (late 1st quarter 2019) to resolve this problem.
The Fixed Issues list for the releases will show an entry for this as follows:
Symptom: Top Interface Utilization "In&Out" sorts by "UtilizationIn ASC" - should sort by "Utilization DESC".
Resolution: Top Interface Utilization views, and similar views for Errors and Discards, now sort by the "In" or "Out" metric when selected, or by the matching total metric, e.g. "Utilization.Avg" when "In&Out" is selected.
(3.6.5_Feb_Update, DE400601, <caseNumber>)