Is there any way to show less decimals than the specified accuracy in Odoo 8 views?

I am trying to manage the following behaviour in Odoo 8:

Set a product price of 5 decimals. For that, I set decimal accuracy of Product Price to 5.

In sale.order view, show only 3 decimals, but calculate the subtotal of the line taking into account the 5 decimals. For this step, I am modifying the view to put this on price_unit field:

<xpath expr="//field[@name='order_line']/tree/field[@name='price_unit']" position="replace">
    <field name="price_unit" digits="(16,3)"/>
</xpath>

But that digits attribute is altering the result.

Example:

I store a product with price 1,00123. I add 5 units of it on a sale order. If I do not use digits in the XML view, the subtotal is 5,01. Because 1,00123 * 5 = 5,00615, rounding this to Account Accuracy (2 decimals) gives 5,01. But if I use digits in XML view, the subtotal is 5,00. Because 1,001 * 5 = 5,005, rounding this to Account Accuracy (2 decimals) gives 5,00.

In fact, I show with logger the line.price_unit value in sale.order.line method _calc_line_base_price. With digits in XML view, line.price_unit values 1,001, without it, it gives 1,00123.

Can anyone tell me how could I show 3 decimals for price unit in XML view without altering the decimal accuracy of 5 decimals? It must be done only for visualization.

Solution

If the xml digits are indeed taken into account for calculations (can't verify that at the moment), you can always have two fields - hidden one for calculations with maximum accuracy, and another for display purposes, which displays already calculated numbers with specified accuracy.