Having accurate bottles weights is crucial in order to have exact measures for remaining volume.
When you place your partially filled bottle on the Bluetooth scale, WISK is doing some number crunching behind the scenes to tell you how much remains in the bottle. If you tell WISK that your bottle is heavier than it is, it will consider a greater proportion of the total weight to be due to the glass bottle itself, rather than due to the remaining liquid. This will impact the volume WISK thinks is in the bottle.
Since the production process of the glassware for these products is not perfect, there will always be a slight variation in bottle weights. Because of this, we take an average of several data points to be used in calculation which is good for the long term.
We encourage you to fine tune your bottle weight data to better reflect the real weights of the particular bottles you have on hand.