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
'product_id': T_TEST.id,
            'product_uom_qty': 60,
            'product_uom': T_GT.id,
            'picking_id': picking_in.id,
            'location_id': self.supplier_location,
            'location_dest_id': self.stock_location
        })
        picking_in.action_confirm()
        self.assertEqual(move.product_uom_qty, 60.00, 'Wrong T_GT quantity')
        self.assertEqual(move.product_qty, 134400.00, 'Wrong T_LBS quantity')
        lot = self.env['stock.production.lot'].create({'name': 'Lot TEST', 'product_id': T_TEST.id})
        self.env['stock.move.line'].create({
            'move_id': move.id,
            'product_id': T_TEST.id,
            'product_uom_id': T_LBS.id,
            'location_id': self.supplier_location,
            'location_dest_id': self.stock_location,
            'qty_done': 42760.00,
            'lot_id': lot.id,
        })
        picking_in.action_done()
        back_order_in = self.env['stock.picking'].search([('backorder_id', '=', picking_in.id)])
        self.assertEqual(len(back_order_in), 1.00, 'There should be one back order created')
        self.assertEqual(back_order_in.move_lines.product_qty, 91640.00, 'There should be one back order created')
class TestRoutes(TransactionCase):
    def test_pick_ship_1(self):
        """ Enable the pick ship route, force a procurement group on the
        pick. When a second move is added, make sure the `partner_id` and
        `origin` fields are erased.
        """