How accurate is the Hill-Rom Stretcher scale system?

How accurate is the Hill-Rom Stretcher scale system?
 

The Hill-Rom scale system has an accuracy of 1% or 2.2 lb (kg), whichever is greater, and an operating range of 0 lb to 700.0 lb (0 kg to 317.5 kg). The scale control is at the foot end of the stretcher.