This jives with measurements I've done before. I ended up running a ping setup for a few months from every region to every other region to get these timings. I was using it to calculate what our GQL latencies would look like if the backing servers were in another region or in the same region as a way to start regionalization work. Sadly we had to depend on those latencies so much that it was deemed a non-starter of an approach. Even us-west-2 (home) to us-east-2 took us from p99 300ms to p99 2.4 seconds. That sweet sweet latency reduction.