I disagree with these numbers, in general. Though of course "noticeable" is subjective and varies by use case as well as by person.
For many people, end-to-end audio latency in a 1:1 conversation becomes noticeable/annoying at 200ms. And in a multi-participant conversation, talking over each other becomes noticeably more common even at 100ms compared to 50ms.
For many people, end-to-end audio latency in a 1:1 conversation becomes noticeable/annoying at 200ms. And in a multi-participant conversation, talking over each other becomes noticeably more common even at 100ms compared to 50ms.