Im not a big fan of Milenco mirros, tbh I dont think I have ever had a set of towing mirrirs regardless of make that I have been happy with. I find the Milencos are difficult for my wife to adjust, as they resist all attempts to adjust slightly and then go with a jump. I did take them out of their ball housing and on both was a little nub from manufacturing. I removed than and applied so light grease inside the socket which helped, but it didnt last long.
Now my dream mirrors are the Reich Power Mirrors, and every time I try to get one, I only need it for the passenger side, they are out of stock. I can adjust the milenco on the drivers side quite happily, its t'other one thats a pain.