In Tax System Tab : To add Sales Taxes and its Alias ,Also Select Tax Formula.
If We have Amount=100 , Tax 1=10% , Tax 2=20%
*And select the Formula [Amount + Tax 1+Tax 2=Total],then The Following Example Illustrate How the Tax Formula Calculation:
the Tax 1 = (Amount/100)x10 = (100/100)x10 = 10
the Tax 2 = (Amount/100)x20 = (100/100)x20 = 20
Total after Tax 1 = Amount+Tax1=100+10 = 110
Total after Tax 2 = Total after Tax 1+Tax2=110+20 = 130
Total =130
*And If select the Formula [(Amount + Tax 1)xTax 2=Total] , then The Following Example Illustrate How the Tax Formula Calculation:
the Tax 1 = (Amount/100)x10 = (100/100)x10 = 10
Total after Tax 1=Amount+Tax1 = 100+10 = 110
the Tax 2 = [(Total after Tax 1)/100]x20 = (110/100)x20 = 22
Total after Tax 2=110+22=132
Total =132