I just repaired a leaking Beverage Air salad station, and recharged with the proper? 9.5 oz of 134 freon as per the label, but suction pressure is only around 4 pounds, seems like it should be around 23. Does anyone know if the label is incorrect? This is a large unit 93" total length with three doors. I have since added about 5 more ounces, and seems to be working better.