If you're going to have 134 fittings on it, why not use 134?

Although I would never use any of the snake oil refrigerants, I do understand how the R12 pricing and availability problems drive people to look for alternatives and most of these people are ignorant of the problems that these snake oils cause for the folks trying to make a living in the auto a/c business. But I REALLY can't understand why they would use anything but 134 for a 134 system.

I suppose that many of these people just believe that they know much more than the people that designed their air conditioners.

Have a great day,