This page explains how Olivier Charlas (USATT# 230405)'s rating went from 1228 to 1226 at the 2021 Butterfly 2-Person Teams Round Robin Tournament held on 14 Aug 2021 - 15 Aug 2021. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.