Mofe, there have been some difficulties in calibrating the device, particularly with faults described as "Linear Error", a firmware update from Alaris has fixed this.
Also there have been issues with a metal plate becomming invisibly warped or damaged from slight abuse, this would also cause calibration errors.
Both faults can be remedied, the motor plate is (from memory) around £40 compared to a fixed price repair.
I would reccomend the updated firmware first though!
