Adding discount on line items via API

I've been trying to create invoices via API from my system. For some reason the item level discount column isn't getting created, following is the payload:

{
    "payment_terms": 0,
    "is_discount_before_tax": true,
    "discount_type": "entity_level",
    "customer_id": 3781685000000130032,
    "discount": 50000.0,
    "line_items": [
        {
            "item_order": 1,
            "rate": 90.0,
            "quantity": 18.0,
            "discount": 10.0,
            "description": "Conversion Credits - \\nCampaigns: Clone: Clone: Clone: 1st_warning, Clone: LCL Testing 1st_warning - 1st to 31st January 2023",
            "item_id": "3781685000000096019",
            "hsn_or_sac": ""
        },
        {
            "item_order": 2,
            "rate": 130.0,
            "quantity": 5.0,
            "discount": 10.0,
            "description": "Conversion Credits - \\nCampaigns: LCL Testing 1st_warning - 1st to 31st January 2023",
            "item_id": "3781685000000096019",
            "hsn_or_sac": ""
        },
        {
            "item_order": 3,
            "rate": 100000.0,
            "quantity": 1.0,
            "discount": 10.0,
            "description": "Additional Campaign Cost",
            "item_id": "3781685000000096019",
            "hsn_or_sac": ""
        }
    ],
    "gst_treatment": "business_gst",
    "custom_fields": [
        {
            "customfield_id": 3781685000000096041,
            "value": "2022/12/31 - 2023/01/31"
        }
    ],
    "template_id": null,
    "payment_terms_label": "Due on Receipt",
    "gst_no": "36AAATS2468J1Z7"
}

Can someone help me with this? Invoice level discount is working fine but item level discount isn't getting created