Rounding problem between amount_residual and amount_total

[CoralieSantos]

Module

account_invoice_triple_discount

Describe the bug

When we confirm an invoice, sometimes there is rounding differences between the amount in amount_residual and the one in amount_total.

To Reproduce

Affected versions: 16.0
On the screenshot, we see that the amount_total is equal to 1765,61$ and the amount_due is equal to 1765,60$.

As I don't know if the screenshot will appears normally, here is the details of the lines on the invoice that I created :
| Label | Quantity | Price | Disc. % | Taxes | Subtotal |
|--------|--------|--------|--------|--------|
| test | 100 | 10.480 | 46.05 | 20% | 565.40 |
| test2 | 10 | 35.440 | 0.00 | 20% | 354.40 |
| test3 | 50 | 3.150 | 50.20 | 20% | 78.43 |
| test4 | 500 | 1.900 | 50.20 | 20% | 473.10 |

Total : 1765.61$
Amount due : 1765.60$

When we look with debug mode on a local base of Odoo, there is a difference between the rounding using to calculate the amount_total and the one to calculate amount_residual.