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
""" Returns an action that will open a form view (in a popup) allowing to work on all the
        move lines of a particular move. This form view is used when "show operations" is not
        checked on the picking type.
        """
        self.ensure_one()
        
        
        
        
        if self.picking_id.picking_type_id.show_reserved:
            view = self.env.ref('stock.view_stock_move_operations')
        else:
            view = self.env.ref('stock.view_stock_move_nosuggest_operations')
        return {
            'name': _('Detailed Operations'),
            'type': 'ir.actions.act_window',
            'view_type': 'form',
            'view_mode': 'form',
            'res_model': 'stock.move',
            'views': [(view.id, 'form')],
            'view_id': view.id,
            'target': 'new',
            'res_id': self.id,
            'context': dict(
                self.env.context,
                show_lots_m2o=self.has_tracking != 'none' and (self.picking_type_id.use_existing_lots or self.state == 'done' or self.origin_returned_move_id.id),