Some coins don't have one fixed weight but a range of weights. Reasons for that may be different varieties of the coin with different weights like e.g. those two:
Or as it happens with mostly old coins, due to old minting techniques the weight differs for each piece, like e.g. here:
My suggestion is to add the possibility to add a range of weight for coins. So under "technical data" we would add 1.4 g – 3.0 g for the first example coin above.
