The scales give a reading which is too low/which is not right. What is going on?
Most probably you have not waited before the 0.0 reading stops blinking. The scales need this time to calibrate. Be sure the scales are standing on the place where you are going to measure, before you start the weighing procedure. Another cause can be that you have moved the scales right before the measurement and the scales must have been switched on automatically during this replacement. If you are moving the scales during calibration (= when the 0.0 reading changes from blinking to a fixed 0.0 reading) it will not give a reliable reading. You should redo the measurement, without moving the scales right before a measurement.