I was wrong, Toro does make a "commercial" mower, now label Heavy Duty but, Now I don't understand. You say that you worked on the Toro commercial mower 22171 in the 80's. That would have been tough as this model was tested as a " commercial" unit starting in 1999 and dropped from their line up after the 2003 model year. If I remember correctly the main reason was the cost $800+ was not living up to the reliability needed by the commercial industry. At my age my memory is waining, so this will be my last post on this subject, as I need what is left of my brain for more important issues.