Hi David,
We have been Northern regional dealers for EcoWater softeners for the last umpteen years, and are acknowledged water softener experts. With salt at about £7 per 25 Kg bag, with a good automatic softener it will cost about 55 pence to regenerate it for every 2000 litres of water at 300 ppm hardness that it treats. If your RO wastes about half the water fed to it (and it could be much worse than that), this works out at 55 pence per 1000 litres of product water.
Obviously the cost will be in proportion to the hardness of your tap water, but my calculations are based on the figures you quoted.
I think you should take the Pozzani forecast with a pinch of salt, and do your own sums, knowing your RO and your water usage. If your water for your business is taken from your own domestic supply, the arguments for installing a softener in your home as a legitimate business expense are very much stronger. We all know the value of "brownie points" from er indoors!
Give me a ring on 01704 541578 if you need any advice.
Yours, Andrew