>>Okay. People adapt methods which gives the result that suits the business PR as required
>
>And starting a discussion about which one is the best method is pretty much like starting one about religion, politics, making tea, best way to do barbecue, coffee etc: guaranteed to become heated and get nowhere.
>
>The practical solution for any app is to have a suite of methods and a config item somewhere where the proper one for the customer will be selected. Add methods as you find new interesting customers.

That's exactly what we're doing here. The calculation method is going to be a configuration option.

However, I need a good link explaining each method in details. So far in a quick google search I didn't find such a page.