Comment 3 for bug 1089229

More info on this:

A case of use:
Description VAT Quantity Unit Unit Price Disc.(%) Price
Handful of peanuts ITAX S 10.000 g 20.00 0.00 200.00 €
Handful of peanuts (big) ITAX S 30.000 g 8.33 0.00 250.00 € <-- This should be: 30.000*8.33=249.90€

In this simple case we see how rounding methods can easily make a 0.10€ difference.

More puzzled now, checking database stored data for sales order and its following invoice:
- Sales order seem to make wrong calculations if UoS is set, because it uses subtotal = unit_price[per UoM] * uom_qty, no matter if UoS is defined. Subtotal computes 250.00€ in the case of use in my previous comment.
- It's following invoice (make invoice from a SO) actually makes calculations again, this time perfectly correct. subtotal = unit_price[per UoS] * uos_qty, thus 249.90€ in the same example.
- In a fresh customer invoice I cannot set a UoS, but only UoM or some other in the same category.

Therefore, I see that a Sale Order may not be accurate and also "secondary unit" is almost useless this way.

Anyone in OpenERP can fix this? At least make "secondary unit" useful in trunk and I would be delighted to try to backport it to 7 and 6.1.