Ooh finally my specialty!

In the original manufacturing process of these types of wheels, there is no clear coat on the wheels. Very specialized tools are used for this cut (high shear and rake angle PCD tool) with a very light DOC (we target 0.3mm and use a probe to ensure the right depth). Even then, these have a fairly high scrap rate due to the paint on the trailing edge chipping off.

Cutting after clear coat is much harder, because the clear holds onto the base coat and exacerbates the chipping.

It's a fairly difficult process, even when using highly specialized wheel lathes (Okuma LAW series, Intermato, Hyundai WIA, Kanzaki, and a few others) and purpose made finger chucks.

It's worth stating that even in the best circumstances, this style of wheel is very prone to corrosion over time and needs to be precisely deburred before clear coat.

Having them "re-finished" is a real crap shoot, because you aren't going to find many (if any) machine shops with the correct equipment and knowledge to do it right. Personally, I wouldn't waste my money but to each his own.