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
show_lots_text=self.has_tracking != 'none' and self.picking_type_id.use_create_lots and not self.picking_type_id.use_existing_lots and self.state != 'done' and not self.origin_returned_move_id.id,
                show_source_location=self.location_id.child_ids,
                show_destination_location=self.location_dest_id.child_ids,
                show_package=not self.location_id.usage == 'supplier',
                show_reserved_quantity=self.state != 'done'
            ),
        }
    def _do_unreserve(self):
        moves_to_unreserve = self.env['stock.move']
        for move in self:
            if move.state == 'cancel':
                
                continue
            if move.state == 'done':
                if move.scrapped:
                    
                    continue
                else:
                    raise UserError(_('Cannot unreserve a done move'))
            moves_to_unreserve |= move
        moves_to_unreserve.mapped('move_line_ids').unlink()
        return True
    def _push_apply(self):
        
        Push = self.env['stock.location.path']
        for move in self:
            
            if move.move_dest_ids:
                continue