Hi,
There's bound to be some confusion with this. There is in fact just one Well Tempered Lab company. It is owned by Bill Firebaugh and his business partner. Unfortunately, neither Transparent (for a good portion of their time producing the old 'tables) nor Stanalog have been authorized to produce the designs or use the WTL name. This is addressed briefly somewhere on the real WTL site, welltemperedlab.net. In a nutshell, Bill Firebaugh, the designer and owner of the designs and trademark, decided to form a new company to handle his latest designs rather than get lawyers involved over issues of the past.
Mike