My global score does not match my ranking history…is this normal?

Yes. It's been like this for years and affect a lot of people, actually everyone I looked at when I tried to find out the same thing some time ago. The recalcs can't eliminate that one. My own difference is fairly small.

Ranking changes are calculated according to headline score, not the one in ranking history.

This is the most eyecatching difference:

https://www.wargear.net/players/info/Atkins/Ranking%20History

Atkins has 1770 global ranking and 6063 in his ranking history. Since it's 1770 being used for calculations he can stay in the 5000-6000 area indefinitely.

The reason for Atkins' exalted ranking is that he was the main victim of the cheating chain of double accounts. Many games he lost to them were reviewed and outcomes changed. Somehow his gigantic ranking plus only transferred to the history and not the headline ranking, and they've stayed apart since.

Thank you Litotes