That's a good point, but I think we need to also consider variability between similar products. For example, whilst a lobster might only be 20% edible, that is

That's a good point, but I think we need to also consider variability between similar products. For example, whilst a lobster might only be 20% edible, that is what people have come to expect of lobsters. All lobsters roughly obey that ratio. In this case, some tablets are delivering on 80 or 90% of their promised capacity whilst others are only managing the vicinity of 25%.