ChessGUI has a bug that affects the scoring of testsuites.
Discard, therefore, all STS Testsuites results got by using ChessGUI.
A bugfix is unlikely to be released within one week.
I found a bug in STS_Tool that affects the estimation of Elo based on scores.
The bug does not affect STS_Tool.ini, nor html results.
The tool shall be updated when ChessGUI is next updated.