How can we create a Complex PO with Advances and Retentions?

Dear Experts,

I have a business scenario regarding complex PO. This scenario is widely used in construction industry. I am looking for the workaround if someone already have done this.

Work Done = 1000

Advance = 100 (10%) We need to less Advance from the Work done.

Retention = 100 (10% Retention on the work done)

Taxable amount = 900 (Work done - Advance)

Total Tax = 135 (15% on the Taxable Amount)

Amount Payable= Work Done - Advance - Retention + Tax i.e. 800+135 = 935

PO needs to be created for the above scenario and then invoice needs to be created for the 935 amount and when we want to create retainage release the amount should be less tax amount i.e. 100.