The reason being is that motor hasn't had enough field testing experience to say their reliable for the pump installer to install them on a regular basis(or an individual like yourself without testing the submersible pump for wear and tear before you buy it used). I would rather buy my "used motor or pump end from a pump installer or well driller that has a test pit. Tried out pumptek for awhile back 2007 before I came around. We went back to a Franklin motor with pentair's products. Lower amperage draw and the higher rating thrust bearing was worth venturing outside the norm from a Franklin motor. Not the first time venturing outside the norm over the years with different motor companies and different pump end companies that perform better with your needs/requirements deep to water.