Quite right, foxmoth.
I'd be the last person to say my ideas were right and others were wrong. I'm still trying to refine our costing mechanism on the basis of the last 2 years experience and a very painful one from a previous group -one day the story of that one will be told!!!
So far we haven't fallen out over the costing method, but I know others have better and more robust accounts - they just wouldn't suit us, at the moment.
I like threads like this, as there is always something to learn from other people's experiences and knowledge