This holds the single highest per-interval delta observed for frames received across the retained sampling window, i.e. the worst one sampling period recorded, not a running total. For one specific historical error-statistics snapshot for an FC port, this is the field to check first after an alert fires, since it shows the worst burst within the window even if the average looks unremarkable. For example, a deltaMax of 45 next to a deltaAvg of 2 tells an admin the problem was one sharp spike rather than a steady low-grade issue.