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
""" Splits qty from move move into a new move
        :param qty: float. quantity to split (given in product UoM)
        :param restrict_partner_id: optional partner that can be given in order to force the new move to restrict its choice of quants to the ones belonging to this partner.
        :param context: dictionay. can contains the special key 'source_location_id' in order to force the source location when copying the move
        :returns: id of the backorder move created """
        self = self.with_prefetch() # 
        if self.state in ('done', 'cancel'):
            raise UserError(_('You cannot split a move done'))
        elif self.state == 'draft':
            # 
            # 
            raise UserError(_('You cannot split a draft move. It needs to be confirmed first.'))
        if float_is_zero(qty, precision_rounding=self.product_id.uom_id.rounding) or self.product_qty <= qty:
            return self.id
        decimal_precision = self.env['decimal.precision'].precision_get('Product Unit of Measure')
        # 
        # 
        # 
        # 
        uom_qty = self.product_id.uom_id._compute_quantity(qty, self.product_uom, rounding_method='HALF-UP')
        if float_compare(qty, self.product_uom._compute_quantity(uom_qty, self.product_id.uom_id, rounding_method='HALF-UP'), precision_digits=decimal_precision) == 0:
            defaults = self._prepare_move_split_vals(uom_qty)
        else: