I have assigned 23% tax to all products and catalog prices includes tax.
The prices are displayed correctly on product pages.
But in the cart I see that both unit prices (excl. tax and incl. tax) for an item are the same and both appear to include tax.
Subtotal prices for an item are the same as well.
"Grand Total Excl. Tax" is a sum of the prices and includes tax.
Tax row is calculated correctly.
"Grand Total Incl. Tax" is greater than expected as if the tax was added twice?
What do I do wrong?
Tax Calculation Method Based On: Total
Catalog Prices: Including Tax
Display Product Prices In Catalog: Including Tax
Display Prices: Including and Excluding Tax
Display Subtotal: Including Tax
Include Tax In Grand Total: Yes
I was aware that origin was important. Mine was set properly. Not doing this would not explain the symptoms I observed though. In my case the totals seemed to be collected in the wrong order.
Eventually adding the following code to my custom module solved the problem.