True, the specs are almost identical. The TSO four-ball test was conducted in 2005. The SSO test was conducted in 2007. The SSO shows a larger wear scar, but the competitive oils show an even greater increase from the 2005 tests. The SSO shows a .04mm increase in wear, but PP shows a .06mm increase. Maybe Amsoil used a different lab that had softer balls?? All things considered, SSO looks to be as worthy an oil as the TSO. Marketing will probably be the biggest difference between them.