This is something tax over taxes.

If there is an ITEM and the price before taxes for it is 2000 when I buy it from outside of my country (IMPORT in my state) then there are three tax-es like:
1. Value of excise (this will add some value to the base price like plus 1000euro, new price = 3000)
2. Customs Tax 10% (3000*0.10=300, then new price = 3300)
3. Tax 16% (3300*0.16 = 528, then the new price = 3828)

When I sell that same product I need only the last Tax 16% after my margin of profit p.s 20%
Then my price before tax = 3960 (becasue 3300 * 1.20)
The Price after tax16% = 4593.60 (because 3960 * 1.16)

Look the screenshot:
[img]http://i571.photobucket.com/albums/ss158/aRTx/TaxOverTax2.jpg[/img]

As you can see I'm using three tax-es to buy and only one tax to sell!
How to handle it?
I try to read WIKI Tax System but I don't know how to do it.