Impacted versions:

[9.0]
Tested in runbot http://174550-9-0-10dcec.runbot10.odoo.com/

Steps to reproduce:

Set the Tax Calculation Rounding Method to "Round Globally" 
Create a Sales Order with the following lines with 7% taxes

1) 5,095.20 
2) 523.20 
3) 80.64 
4) 54.12 
5) 182.00 
6) 186.20 
![image](https://cloud.githubusercontent.com/assets/16055718/19144073/309aa082-8bda-11e6-81d0-2461c4e9a467.png)

Create a Sales Invoice with the same lines with 7% taxes
![image](https://cloud.githubusercontent.com/assets/16055718/19144078/38048b58-8bda-11e6-9c2b-4b501cfa1e12.png)

Current behavior:

The total taxes in Sales Order are $477.48 

The total taxes in Sales Invoice are $477.50 

Expected behavior:

Both the total taxes in Sales Order and Sales Invoice should be 477.50 

Video/Screenshot link (optional):

addons/sale/sale.py
"""
        Create procurements based on quantity ordered. If the quantity is increased, new
        procurements are created. If the quantity is decreased, no automated action is taken.
        """
        precision = self.env['decimal.precision'].precision_get('Product Unit of Measure')
        new_procs = self.env['procurement.order'] 
        for line in self:
            if line.state != 'sale' or not line.product_id._need_procurement():
                continue
            qty = 0.0
            for proc in line.procurement_ids:
                qty += proc.product_qty
            if float_compare(qty, line.product_uom_qty, precision_digits=precision) >= 0:
                continue
            if not line.order_id.procurement_group_id:
                vals = line.order_id._prepare_procurement_group()
                line.order_id.procurement_group_id = self.env["procurement.group"].create(vals)
            vals = line._prepare_order_line_procurement(group_id=line.order_id.procurement_group_id.id)
            vals['product_qty'] = line.product_uom_qty - qty
            new_proc = self.env["procurement.order"].create(vals)
            new_procs += new_proc
        new_procs.run()
        return new_procs
    @api.model
    def _get_analytic_invoice_policy(self):