Hi Odoo Community - the goal is to apply compounded taxes to an order. One tax is taken from the product and the other from the partner. I'm making use of Fiscal Positions so it can be defaulted to the partner. Here's my use-case to better explain the issue.

Tax 1:

• Set in Product 1
• 12%
• Included in Price

Tax 2:

• Set in Customer 1>Fiscal Position X
• -1%
• Not Included in Price

Fiscal Position X:

Tax on Product        Tax to Apply

Tax 1                            Tax 1

Tax 1                            Tax 2

When the system sees Tax 1 in the Product 1 and Customer 1 is selected, it sets the Taxes to Tax 1+Tax 2. However, the calculated amount is not correct because Tax 1 is set to be "Included in Price" while Tax 2 is not.

Sample:

Unit Price: 1500

Untaxed Amount: 1339.29

Tax 1: 1500/1.12 = 160.71

Tax 2: 1500*0.01 = 15 >> Wrong because it should use 1339.29 as the tax base

Total: 1339.29 + 160.71 - 15 = 1485 >> Wrong

When I do this manually, by entering both taxes in the order line, it is calculated correctly. 

Sample:

Unit Price: 1500

Untaxed Amount: 1339.29

Tax 1: 1500/1.12 = 160.71

Tax 2: 1500*0.01 = 13.39

Total: 1339.29 + 160.71 - 13.39 = 1486.61 >> Correct

How can I go about this? Thank you.