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
assigned_moves |= move
                    else:
                        partially_available_moves |= move
                else:
                    # 
                    # 
                    # 
                    # 
                    # 
                    move_lines_in = move.move_orig_ids.filtered(lambda m: m.state == 'done').mapped('move_line_ids')
                    keys_in_groupby = ['location_dest_id', 'lot_id', 'result_package_id', 'owner_id']
                    def _keys_in_sorted(ml):
                        return (ml.location_dest_id.id, ml.lot_id.id, ml.result_package_id.id, ml.owner_id.id)
                    grouped_move_lines_in = {}
                    for k, g in groupby(sorted(move_lines_in, key=_keys_in_sorted), key=itemgetter(*keys_in_groupby)):
                        qty_done = 0
                        for ml in g:
                            qty_done += ml.product_uom_id._compute_quantity(ml.qty_done, ml.product_id.uom_id)
                        grouped_move_lines_in[k] = qty_done
                    move_lines_out_done = (move.move_orig_ids.mapped('move_dest_ids') - move)\
                        .filtered(lambda m: m.state in ['done'])\
                        .mapped('move_line_ids')
                    # 
                    # 
                    moves_out_siblings = move.move_orig_ids.mapped('move_dest_ids') - move
                    moves_out_siblings_to_consider = moves_out_siblings & (assigned_moves + partially_available_moves)
                    reserved_moves_out_siblings = moves_out_siblings.filtered(lambda m: m.state in ['partially_available', 'assigned'])
                    move_lines_out_reserved = (reserved_moves_out_siblings | moves_out_siblings_to_consider).mapped('move_line_ids')
                    keys_out_groupby = ['location_id', 'lot_id', 'package_id', 'owner_id']
                    def _keys_out_sorted(ml):