Kohler K-304 valve problem...

I had a recent install of a Kohler K-304 pressure balancing valve with a tub spout diverter. I had a plumber rough in the new valve. I recently installed the trim kit and discovered that water runs through the shower any time the water is turned on even when the diverter is not engaged. I come to find the plumber installed the valve upside down (top-down) . This may be a long shot but- is there any way to correct the problem without opening up the wall and removing / re-installing the valve top-up?? Many thanks for your help.

valve

You can repipe it so the tub port goes to the spout and the shower goes up, without removing the valve, but that might still cause the same type of problem and you will still have to open the wall, so you might as well do it right and turn the valve over.