Adding Down Payment Invoice invalid amount

While adding Down Payment via servise layer API I'm getting error message .

{
 "error": {
 "code": -5002,
 "message": {
 "lang": "en-us",
 "value": "10001279 - Down payment invoice total amount must be equal to the payment amount 1,00 PLN"
 }
 }
}

I've checked and the amount is correct. I made some tests in Postman and I couldn't add any new, even with correct amount.

I've made several tests with use of diffrent variants of request, here is one example.

{
    "CardCode": "D0001",
    "DocTotal": 1.00,
    "DocumentLines": [
        {
            "ItemCode": "1000",
            "Quantity": "1",
            "TaxCode": "T1",
            "UnitPrice": 1,
            "BaseLine": "0",
            "BaseType": "203",
            "BaseEntry": "87"
        }
    ],
    "DownPaymentType": "dptInvoice"
}

Here is another.

{
    "CardCode": "D0001",
    "DocumentLines": [
        {
            "ItemCode": "1000",
            "Quantity": "1",
            "TaxCode": "T1",
            "UnitPrice": 1,
            "BaseLine": "0",
            "BaseType": "203",
            "BaseEntry": "87"
        }
    ],
    "DownPaymentType": "dptInvoice"
}

In any case I receive the same result as mentioned above.

Any help will be apreciated.

Kind regards

Arkadiusz