The instruction for the valve state "The lower port of the thermostatic mixer is intended for use with a bath spout only. If a bath spout is not used with this product, the lower port must be plugged." My shower design has for functions (3 body sprays, shower head, wand, and rain shower head). Each with a separate volume control. Has anybody come off the bottom port of this valve to a volume control then to a shower function instead of caping it and taking all four functions off the top port?