Hello Daniel,

In order to access 3 digits, you have to change the rounding precision of 0.00100 in UoM categories.

you can find and create more UoM in Inventory > Configuration > Units of Mesures > UoM categories.

Also, you can select more than one UoM for one product. As an example, you can purchase and sell as 'Kg' and use it in manufacturing as 'gm' by selecting fields on the product page.

Best regards,
Harmit (write.harmit@gmail.com)