Is there any way to set a specific decimal precision in the packaging by products?

We need to set a value with eight decimals but only for the quantity registered in Contained quantity (Inventory Tab in Product Form). We already set the precision decimal to four decimal digits that we need in sales and purchase module. But, for some products the value is so small (0.00117647) and its value is only for reference (f.e. 850 units for box) no sales or purchases are made with this packaging.

Thanks in advance