Take the first reading on the scale and accept it – even if you think it’s wrong.
When you buy produce at the market does the deli person weigh it over and over again hoping to get a lower reading for you? No.
If they lift the produce once, twice, then replace it on the scale, they’re looking for a larger reading, so they can charge you more. If they do it – because of their experience doing it and their experience getting away with or not getting away with doing it – they’ll usually do it only once to achieve a greater weight.