I have done quite a bit of work over the past few days and I have gotten the new charge system working really great. In actual fact I think that it is working better than I ever imagined.
ATM I have not built all the componets that I want to build, but it is still kicking butt. Also remember this new charging system that has been built replaces shipping, discounts, tax modules and is all pretty much just point and click to build new charges.
The majority of the time store owners will not need developers to build new charges or discounts. However for integration into shipping companies will need to work to build up the calculation componet to get the prices from the shipping API, but I see there being module being released for integration into shipping companies, and the component API is very easy so it is not hard.
The other thing is that if you want to you can use multiple shipping companes together to give the customer the best price. So you could offer standard post or a shipping company to give the customer the options. Not only that the store owner can actually use different shipping methods for different delivery destinations. Also if someone really wanted to they could write new filter componets for determining which warehouse to ship from and then calculate the changes based upon different start points. (Note I have no need for this, So I have not developed it, But someone could develop a warehouse module to handle this).
These charges can also be defined where they are added in the system, so you can add them to a product or to the transaction. So role based discounts are just a filter, and nothing more. Even if you want to charge anonymous customer a higher price, a couple of clicks and there you go.
This also means that I do not have to be an expert and every different type of tax around that world. I saw a tweet that another open source cart that they were having a meetup on how to implement VAT in their cart. e-Commerce can leave this to the store owner who needs to know how to this anyway, and I don't need to worry about whether a store owner doesn't like how I implemented it, since they will define it.
I have attached Australian GST as an example. It is pretty simple.

Once I get some breathing space I am going to add an import/export system for charges so we can build you a library of these for people to use.
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Comments
Calculation example
Please Gordon, can you provide an example how to setup a calculation, i.e. 5% VAT? Thanks!