Can someone help me set up the tax after retention of 10% sale
Please see the below computation.

Renovation fee:                 100,000

less retention 10%:            -10,000 (cannot be treated as discount because it has a journal entry)  

untaxed amount:                79,200

tax-inclusive 12%:              10,800.00

total:                                    90,000

can someone help me achieve this on customer invoices?