How to calculate player ping/latency for matchmaking?

I noticed that for matchmaking requests, for each player in the ticket, you have to specify a latency map field. However, I am wondering how twe should calculate these values. I have stumbled across these sites: https://www.cloudping.info/ https://cloudpingtest.com/aws And I was wondering how these sites calculated these values?

Also, I wanted to know if StartMatchmaking behaved similarly to StartGameSessionPlacement with regards to placing players on fleets in regions with better connection speeds relative to the players. In the documentation for StartGameSessionPlacement,

When placing a game session, by default Amazon GameLift tries each fleet in the order they are listed in the queue configuration. Ideally, a queue's destinations are listed in preference order.

Alternatively, when requesting a game session with players, you can also provide latency data for each player in relevant Regions. Latency data indicates the performance lag a player experiences when connected to a fleet in the Region. Amazon GameLift uses latency data to reorder the list of destinations to place the game session in a Region with minimal lag. If latency data is provided for multiple players, Amazon GameLift calculates each Region's average lag for all players and reorders to get the best game play across all players.

I wanted to know if this logic applied to how FlexMatch matches players even if you don't specify a rule in the matchmaker's rule set that is directly related to latency.