While helping my grandson remodel his bath, we installed new shower/tub valve, however, unknowingly installed the tub spout pipe too short. (minimum lenght 8"). Mine is 6.5" valve to elbow. When we got finished and tried out the system water came out the shower as well as the spout with the diverter open. Very low flow of water from the spout and small stream from shower. Delta says minimum 8" distance between the valve and elbow or not going to work. The tub surround is tiled and I don't want to remove the tile if there is a workaround. If the 8" is just the length of the pipe can I just make a "swing joint " in the pipe to lengthen it or is the elevation important? The pipe is cpvc.