I hope you'll forgive the nitpick, but those percentiles aren't a measure of consistency, they're a measure of the impact of outliers on the high end. E.g. [30,30,30,30,30,30,30,30,60,60] (8 30's and 2 60's) has the same p90/95/99 as [20,20,20,20,40,40,40,40,60,60] (4 20's, 4 40's, and 2 60's), but they're not equally consistent.

They're probably fine here, because I don't think we actually care about consistency (I wouldn't complain if suddenly half my packets had lower latency) we care about the worst case latency and how often it happens.

Standard deviation is what I'd use if I was measuring consistency.