If we use calculator tools on Amt or Costing field, it is not respecting currency preference for precision.
That's valid and is intended that way, the price field doesn't need to have Amount precision - and there are some cases where is required to have many decimals in the price.
Indeed, I think we solved a bug where the price was being rounded, and that leads to problems when managing some units of measure.
The important thing is that when calculating the Line Amount it does the rounding.
This is based on one of request from Steven and thought good to fix same in iDempiere too. Let’s wait for 's thought and if it don’t sound good then we can close this ticket.