How to count the tax on Base price, not after Discount using Coupons?

I have 2 compound taxes.
1. 5% SC
2. 10% PB1

And then I have promo 20% discount using Coupons Code

Right now The tax are charged after the discount

Base Price IDR 10.000
Discount IDR -2.000
Subtotal IDR 8.000
SC 5% IDR 400 ( 5% x IDR 8.000) *subtotal
PB1 10%. IDR 840 ( 10 X IDR 8.400) *compound tax
GRAND TOTAL. IDR 9.240 (Subtotal + SC + PB1)

Is it possible to count the tax on the base price?
Base Price IDR 10.000
Discount IDR -2.000
Subtotal IDR 8.000
SC 5% IDR 500 ( 5% x IDR 10.000) *base price
PB1 10%. IDR 1050 ( 10 X IDR 10.500) *compound tax
GRAND TOTAL. IDR 9.550 (Subtotal + SC + PB1)