Create invoices via API with gross amount in Netsuite

Question

I'm trying to post invoices via API. Using the net amount works fine

{
    ...
    "item": {
        "items": [
            {
                "item": {
                    "id": "3362"
                },
                "amount": 100,
                "quantity": 1,
                "description": "Description",
                "department": {
                    "id": "1",
                    "refName": "Sales"
                },
                "itemSubtype": {
                    "id": "Sale",
                    "refName": "Sale"
                },
                "itemType": {
                    "id": "NonInvtPart",
                    "refName": "NonInvtPart"
                },
                "location": {
                    "id": "206",
                    "refName": "Location"
                },
                "class": {
                    "id": "2633",
                    "refName": "Some Class"
                }
            }
        ]
    }
}

This will automatically apply the items tax rate (e.g. 20%) and show a gross of 120 on the invoices line.

I'd love to be able to post the invoice with a gross amount of 120 instead, and let Netsuite calculate the net. This is because I'm always getting amounts with tax included, without knowing the tax. I'd like to keep taxing logic in Netsuite. Xero has the tax inclusive/exclusive option (https://developer.xero.com/documentation/guides/how-to-guides/tax-in-xero#tax-inclusive-vs-tax-exclusive).

What's the recommended way?