John, metric probably would be less ambiguous. 20 oz needs to be interpreted by context, is it measuring weight or volume? 0.6 liters is clearly referring to volume, while .6 kg is clearly mass (or weight on this planet). Maybe if we used the English unit of force/weight the slug instead of ounces we'd be better off. However, I'm not sure I'd want to order ~16 slugs of cheese (instead of 8oz/0.5lb).