I think the new Behmor AB would be a good upgrade at $399 with #8 of green coffee. https://www.roastmasters.com/behmor.html
It's probably the case where Joe has reached the point where "economy of scale" comes into play. There also could be other parts upgraded inside the machine that are not mentioned. What about US tariffs on Chinese ovens?
The Behmor still does not have any competition at it's price point and capacity; and can roast other foods, nuts/cacao. Yes it's an entry level machine, however there are a lot of owners who have outsmarted the Behmor and roast outstanding coffee.