This page explains how Jason Leon (USATT# 229470)'s rating went from 1644 to 1613 at the Butterfly 2021 September BTTC Open held on 24 Sep 2021 - 26 Sep 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.