I wa careful to level them the best I could. Set up a tripod in the center. Put a laser level on it. Leveled the laser. Then rotated it towards each scale. Measured down from the laser line to the scale itself. Yhen shimmed the scales to the same height with-in about 1/8". Temp about 65 degrees in the garage, no sun shining on them. I will try swapping the scale and cables. Along with double checking connections. Cant get back on it until monday. It does have preload. But on the scales it changes between around 50lbs to about 85lbs,
Doug