Regional marketing is my guess. Keep in mind that Toshiba in differnet parts of the globe are almost like separate entities. Tosh Canada & Tosh US sell very different Notebooks from time to time.
In the US there are no sat pro's anymore and some of the modles listed there as Satellites ae sold in the UK and other parts under the Sat. Pro badge. The differences in warranty are also regional. Int he US all Tosh noteboks come standatrd with a one year warranty. In Canada & Australia the Tecras come standard w/a 3 year wwarranty. It may well be that wherever you are the Satellites have a 1 year, the pro's a 2 year and the the Tecra's a 3 year, but I wouldn't generalize it for the whole world.