SIGN IT - How to represent mandatory cash rounding

Since January 1, 2018, 1 and 2 cent coins are no longer produced. 

Under Italian law (DL n. 50/2017), the total amount due, if paid entirely in cash, must be rounded to the nearest €0.05:

• €0.01–€0.02 → rounded down to €0.00 
• €0.03–€0.04 → rounded up to €0.05 
• €0.06–€0.07 → rounded down to €0.05 
• €0.08–€0.09 → rounded up to €0.10

This rule applies only if the payment is made entirely in cash.

1. Rounding down 
   The difference (€0.01 / €0.02) is recorded as a discount at payment level: payments[type=CASH].details.discount

   Example: if total_vat.inclusive is €23.02, the cash amount due is €23

   "payments": [
           {
             "type": "CASH",
             "details": {
               "amount": "23.00",
               "discount: "0.02"
             }
           }
         ]

   Note: The "Documento Commerciale Online" web procedure on which SIGN IT lite is based technically tolerates a discrepancy of up to €0.02 between the document total and the payment total. While it would therefore be technically possible to represent only 23.00 in the example above, including the discount is more consistent with the approach defined in the traditional RT technical specifications.
    

2. Rounding up 
   The difference (€0.01 / €0.02) is added to the payment amount:  payments[type=CASH].details.amount

   Example: if total_vat.inclusive is €23.09, the cash amount due is €23.10

   "payments": [
           {
             "type": "CASH",
             "details": {
               "amount": "23.10"
             }
           }
         ]