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
self.ensure_one()
        # 
        location_dest_id = self.location_dest_id.get_putaway_strategy(self.product_id).id or self.location_dest_id.id
        vals = {
            'move_id': self.id,
            'product_id': self.product_id.id,
            'product_uom_id': self.product_uom.id,
            'location_id': self.location_id.id,
            'location_dest_id': location_dest_id,
            'picking_id': self.picking_id.id,
        }
        if quantity:
            uom_quantity = self.product_id.uom_id._compute_quantity(quantity, self.product_uom, rounding_method='HALF-UP')
            vals = dict(vals, product_uom_qty=uom_quantity)
        if reserved_quant:
            vals = dict(
                vals,
                location_id=reserved_quant.location_id.id,
                lot_id=reserved_quant.lot_id.id or False,
                package_id=reserved_quant.package_id.id or False,