ADempiere and iDempiere – Calculate Tax on BillTo vs ShipTo Address

Hi Everyone,

The purpose of this post is to help you fix a tax calculation error. By default, ADempiere calculates Sales Order and Customer Invoice tax based on the Bill To Address. This is not correct, at least not in the US.

The tax code can be somewhat confusing at first look. Let’s break it down to help you understand the code and, ultimately, fix the issue. There are two general areas where taxes are evaluated:

1. When fields are modified (example: product and charge) that can change the tax consequences, the system will update the document line’s tax ID in real time. These changes happen in the CalloutOrder and CalloutInvoice classes. As you walk your way back through the code, you will land on the Tax.java’s getTax method at around line 489. You will notice that that even though the method passes both the ShipTo and the BillTo, the code only uses the BillTo to calculate tax. The simple fix is to use the ShipTo when available, else use the BillTo.
2. When document lines are saved, the MOrderLine’s or MInvoiceLine’s beforeSave method will call on the setLineNetAmt method. This method uses the above TaxID to determine the total tax from this line.

The details listed in bullet one solve the stated issue. Bullet number two is included for reference to help complete the picture. If you would like help understanding how ADempiere or iDempiere function, let me know.

I hope this helps!!

Please note that ADempiere, iDempiere and Openbravo are forks or copies from Compiere. Therefore, they have similar abilities mentioned above. The biggest difference is that ADempiere and iDempiere are pure open source. There are no features held behind a commercial or paid license.