Update Appointment details using PUT Request not working

Hi @Naveen Boga  thank you for quick reply, 

This is the PUT call URL using in Postman.
PUT: http://localhost/AcumaticaERP/entity/Default/20.200.001/Appointment?$expand=Details
BODY:  

{
    "AppointmentNbr": {"value": "ABCD123456-1"},
     "ServiceOrderType": {
        "value": "ABCD"
    },
    "Details": [
        {
        "id": "111ab111-2222-bc22-c23-c8f750455784",

            "LineType": {
            "value": "Stock"
        },
        "InventoryID": {
                    "value": "AB_AB_ABCD"
                },
         "ActualQty": {
                    "value": 2.000000
                },
                "BillableQty": {
                    "value":1.000000
                },
                "EstimatedQty" : {
                    "value":1.000000
                },
             "Note": {
            "value": "For Testing from Postman"
        }
        }
    ]
}

I tried with few scenarious  where status of an Appointment is Inprogress or completed

This is the code I’m using in API:

public async Task<Acumatica.Default_20_200_001.Model.Appointment> AddStock(string token, requestDTO request)
        {
                string expand = "Details";
                var newDetail = new AppDetails
                {
                    ID = request.Id,
                    LineType = request.LineType,
                    InventoryID = request.InventoryId,
                    EstimatedQty = request.EstimatedQty,
                    BillableQty = request.BillableQty,
                    ActualQty = request.ActualQuantity,
                    Note = request.Note
                };
                var updatedAppointment = new Acumatica.Default_20_200_001.Model.Appointment
                {
                    AppointmentNbr = request.AppointmentNbr,
                    ServiceOrderType = request.ServiceOrderType,
                    Details = new List<AppDetails> { newDetail }
                };
                AppointmentApi appApi = GetApiClient(token, apiClient);
                Acumatica.Default_20_200_001.Model.Appointment result = await appApi.PutEntityAsync(updatedAppointment, expand: expand);
                return result;
        }

For both Postman and API the result is same as below.

Scenario 1: If the AcutalQty is removed from the code/body the rest of the fields are updating as expected.
Scenario 2: If the ActualQty is null then getting : "exceptionMessage": "Nullable object must have a value". 
Scenario 3: if the ActualQty is provided with any value such as 2, 2.0, 2.000000, “2.0”, 0 then getting : "exceptionMessage": "An error occurred during processing of the field Qty: Specified cast is not valid.." 

While adding a new line in the details tab from API
Scenario 1: if the ActualQty is null then new line is adding as expected 
Scenario 2: if the ActualQty is provided with any value such as 2, 2.0, 2.000000, “2.0”, 0 then getting : "exceptionMessage": "An error occurred during processing of the field Qty: Specified cast is not valid.." 

Hi @Django Thank you,  but I prefer using the same field I want to know the correct reason why it is not working so is there any way I can find it or any other way we can do it like a work arround without adding a new field.