Also worth mentioning the slightly fuzzier problem that the effects on user satisfaction from latency is not linear. A user that experiences four 125 ms page lo

Also worth mentioning the slightly fuzzier problem that the effects on user satisfaction from latency is not linear. A user that experiences four 125 ms page loads followed by one 500 ms page load is less happy than the user experiencing five 200 ms page loads. So the user experience of your system is strongly driven by the tails of the latency distribution. Practically all of the useful information is beyond 95 %, not below it.