617 Camera lens mount Q

[Momentz]

With all 617 camera, do you have to buy a new lens mount with every new lens you buy? i was looking at the gaoersi one and it looks like i have to add $400 everytime to the cost of the lens for a new lens mount obviously for different sizes, is this just the case with the gaoersi? do other 617 have adjustable lens mounts so you can mount anything from a 90mm - 210 etc etc with out changing lens mounts?

[Aender Brepsom]

As far as I know, every focal length requires another cone, as there is no bellow that would make longer extension possible. That's the same for any 6x17 camera, Linhof, Gaoersi, Fotoman, Horseman, Fuji, ...
Another thing to remember is that even if 2 lenses could use the same cone, it would still be too much hassle to mount them in the field every time you wish to use the other lens. The same goes for view camera lenses; each one has its own panel and you wouldn't start unmounting them every time you need to use another lens. The difference here lies in the price for the panels vs the cones.
You may start to see why some people prefer a view/field camera with a 6x17 back.