How do they measure this? (They have different latency between the same nodes depending on direction)
That is, they think pings could be treated in a different way but with a TCP connection establishment you are measuring what most internet users want to do over the link.
As for different readings from different directions you can get that with both pings and TCP open, it's just maybe more noticable and exacerbated with the longer and multiple-message nature of a TCP open.