A related point from someone who grew up in the UK (20 fluid ounces = 1pint), lived for 14 years in the U.S. (16 fl oz = 1 pint), and now lives in metric France, I would really recommend that everyone works in metric units for calculating treatment dosages, WC rates etc. It really much simpler and therefore much less prone to error. Teaspoons, tablespoons, cups and fluid ounces are all replaced by ml and moving from ml to litres couldn't be easier - especially compared with relating, for example, fluid ounces to gallons.
And a bonus: 1 litre of water weighs 1 kilogram, so moving between liquid volume and weight is simplified.
