update price breaks' DFF for an existing blanket purchase agreement via REST API

Summary:
Is it possible to update the DFF fields in the price break using the REST API

Content (please ensure you mask any confidential information):

REST API used: /fscmRestApi/resources/11.13.18.05/purchaseAgreementImportRequests

Payload Used:{

    "BatchId": 20260409154943,

    "ActionCode": "UPDATE",

    "DocumentTypeCode": "BLANKET",

    "ApprovalActionCode": "SUBMIT",

    "ChangeOrderDescription": "0",

    "ProcurementBU": "***",

    "AgreementNumber": "***",

    "Supplier": "***",

    "SupplierSite": "***",

    "lines": [

        {

            "ActionCode": "SYNC",

            "LineNumber": 2,

            "priceBreaks": [

                {

                    "PriceBreakNumber": 3,

                    "Price": 30.0,

                    "Attribute1": "N", //Not getting updated

                    "Attribute6": "2", //Not getting updated

                    "Attribute7": "30", //Not getting updated

                    "ShipToLocation": "****",

                    "ShipToOrganizationCode": "**"

                }

            ]

        }

    ]

}

From the output of this we get 'InterfaceHeaderId' needed to invoke another REST API to send SUBMIT as

approvalActionCode:
/fscmRestApi/resources/11.13.18.05/purchaseAgreementImportRequests/{InterfaceHeaderId}/action/importPurchaseAgreements

Everything except the Attribute1, Attribute6, Attribute7 are not getting updated it is same as when it was created.