The readout fluctuations are part of the scale's internal electronics. It's best to just to weight yourself just once each time and go with that reading rather than fret over the differing readings. Also, fluctuations can also happen if your floor is not 100% level. If this is the case, be sure that the scale is always in the same spot each time you weigh yourself. What's most important is the weight change over a period of time.
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