How to have a Sales Order Tax of 7% to be added base on total amount of the Sales (as in Case B below),
instead of itemised Tax total (Case A)?

Case A:-
Item 1: Amount $1.20 X 7% Tax = $0.08
Item 2: Amount $1.30 X 7% Tax = $0.09
Total : Amount $2.50 with itemised Tax = $0.17 (this is NOT our correct tax calculation)

Case B:-
Item 1: Amount $1.20
Item 2: Amount $1.30
Total : Amount $2.50 X 7% Tax = $0.18 (Tax is correctly calculated from the total amount)