Board Game Arena

I came in last place with a match against 2 players with 102 and 146 ELO when I had 217 ELO, and I lost 19 points, but when I had no points and I played against someone who had 169 ELO, they only lost 15 points.

https://boardgamearena.com/table?table=605918975
You lost against two players. You lost -9.90 and -9.03

https://boardgamearena.com/table?table=589000385
They lost against one player. They lost -14.51

And that's even without taking into account the possible differences in K factor https://boardgamearena.com/faq?anchor=faq_account_elo

Oh, thanks for posting the information regarding calculating ELO