https://github.com/odoo/odoo/blob/b192431aeecc59b48898ce9c6f276b82d65cbfa6/addons/stock/models/stock_move.py#L1026

rounding_method ='UP'
I think it **need be changed to:**
rounding_method ='HALF-UP'

I get this message then I Verify new Delivery(stock.picking):

> The initial demand has been updated.
> My Product
> Quantity : 5.951 -> 5.949999999999999 

and
> The initial demand has been updated.
> My Product
> Quantity : 5.951 -> 5.951 


How I did it(you can also repeat this error): Create new Product > add Qty on hand > Create SO > Add Product with quantity 5.5 > Verify > open Delivery > add Delivered qty 5.95 > Verify > Get trouble: odoo change my qty to 5.951
![default](https://user-images.githubusercontent.com/34191760/39213952-9b246470-481b-11e8-8e06-a074b1044536.png)

You can try execute in python:
5.95 - 5.5 = 0.4500000000000002

Look at the code:
```
            extra_move_quantity = float_round(
                self.quantity_done - self.product_uom_qty,
                precision_rounding=self.product_uom.rounding,
                rounding_method ='UP')
```
if you setup parameters like this:
```
            0.451 = float_round(
                5.95 - 5.5,
                precision_rounding=self.product_uom.rounding,
                rounding_method ='UP')
```
Then you get 0.451.  This is wrong!
Try:
```
            0.45 = float_round(
                5.95 - 5.5,
                precision_rounding=self.product_uom.rounding,
                rounding_method ='HALF-UP')
```
0.45 = 5.95 - 5.5
addons/stock/models/stock_move.py
move.write({'picking_id': picking.id})
            # 
            # 
            # 
            # 
            # 
            if recompute:
                move.recompute()
        return True
    def _get_new_picking_values(self):
        """ Prepares a new picking for this move as it could not be assigned to
        another picking. This method is designed to be inherited. """
        return {
            'origin': self.origin,
            'company_id': self.company_id.id,
            'move_type': self.group_id and self.group_id.move_type or 'direct',
            'partner_id': self.partner_id.id,
            'picking_type_id': self.picking_type_id.id,
            'location_id': self.location_id.id,
            'location_dest_id': self.location_dest_id.id,
        }
    def _action_confirm(self, merge=True, merge_into=False):
        """ Confirms stock move or put it in waiting if it's linked to another move.
        :param: merge: According to this boolean, a newly confirmed move will be merged
        in another move of the same picking sharing its characteristics.
        """
        move_create_proc = self.env['stock.move']
        move_to_confirm = self.env['stock.move']
        move_waiting = self.env['stock.move']
        to_assign = {}