Ignite UI version: 2018.2

When I set defaultValue in the iggrid initialization (columnSettings): works!
When I change defaultValue in the rendered event: works!
When I change defaultValue in the saveChanges event after committing the dataSource: doesn't work
Changing another another parameter, f.e. "required" in the saveChanges event after committing the dataSource works too, so I suppose there's a problem changing defaultValue programmatically after initialization.

Is there a work around?

My code:

var grid = $("#CustomerStartupNormenGrid");
$.ajax({
	type: "GET",
	cache: false,
	url: urlCustomerStartup_GetNormen,
	data: { klantNr: webCustomer.Klantnr, login: webUser.Gebruikersnaam, languageCode: languageCode },
	dataType: "json",
	async: false,
	success(response, status, xhr) {
		if (response) {
			var ct = xhr.getResponseHeader("content-type") || "";
			if (ct.indexOf("ERROR") === -1) {

				//Grid Initialization
				grid.igGrid({
					language: languageCode.toLowerCase(),
					dataSource: response,
					responseDataKey: "OpstartNorm",
					updateUrl: urlCustomerStartup_SetNormen,
					autoGenerateColumns: false,
					primaryKey: "Volgnummer",
					autoCommit: true,
					width: "100%",
					height: "800px",
					columns: [
						{ headerText: "", key: "Volgnummer", dataType: "number", hidden: true },
						{ headerText: "", key: "Klantnr", dataType: "string", hidden: true },
						{ headerText: "", key: "Login", dataType: "object", hidden: true },
						{
							headerText: "Afdelingscode",
							key: "Afdelingscode",
							dataType: "string"
						},
						{
							headerText: "Artikelnr",
							key: "Artikelnr",
							dataType: "string"
						},
						{
							headerText: "Telvolgorde",
							key: "Telvolgorde",
							dataType: "number"
						}
					],
					features: [
						{
							name: 'Updating',
							editMode: "dialog",
							rowEditDialogOptions: {
								width: "500px",
								height: "700px",
							},
							columnSettings: [{
								columnKey: "Klantnr",
								defaultValue: webCustomer.Klantnr
							},
							{
								columnKey: "Login",
								defaultValue: [webUser.Gebruikersnaam]
							}, {
								columnKey: "Afdelingscode",
								required: true,
								editorType: 'combo',
								editorOptions: {
									mode: "dropdown",
									dataSource: response.Afdelingen,
									textKey: "Naam",
									valueKey: "Code"
								}
							}, {
								columnKey: "Artikelnr",
								required: true,
								editorType: 'combo',
								editorOptions: {
									mode: "dropdown",
									dataSource: response.Artikels,
									textKey: "Omschrijving",
									valueKey: "Artikelnr",
									validatorOptions: { language: languageCode.toLowerCase() }
								}
							}, {
								columnKey: "Telvolgorde",
								editorType: 'numeric',
								defaultValue: 0,
								required: true,
								allowSorting: true,
								currentSortDirection: 'ascending',
								editorOptions: {
									validatorOptions: { language: languageCode.toLowerCase() }
								}
							}],
							editRowEnded: function (evt, ui) {
								if (ui.update) { //ui.rowUpdate
									$("#CustomerStartupNormenGrid").igGrid("saveChanges",
										function (data) {
											if (data.ids.NewId > 0) {
												setTimeout(function () {
													grid.igGridUpdating("setCellValue",
														data.ids.OldId,
														"Volgnummer",
														data.ids.NewId); // Line 5

													$(
														"#CustomerStartupNormenGrid > tbody > tr[data-id='" +
														data.ids.OldId +
														"']").attr("data-id", data.ids.NewId); // Line 6
												},
													100);
											}

											grid.data("igGrid").dataSource.commit(); // Line 8
											grid.data("igGrid").dataSource.allTransactions().length = 0; // Line 9

											//Show feedback
											var message = TranslationDAL.localizedStrings["GridUpdated"][languageCode];
											showFeedback("CustomerStartupNormenUpdatedMessage", message);

											CalcDefaultTelvolgorde();
										},
										function (jqXHR, textStatus, errorThrown) {
											alert(jqXHR.responseJSON.ErrorMessage);
										});
								}
							},
							rowDeleted: function (evt, ui) {
								var message = TranslationDAL.localizedStrings["GridUpdated"][languageCode];
								showFeedback("CustomerStartupNormenUpdatedMessage", message);

								grid.igGrid("saveChanges");

								CalcDefaultTelvolgorde();
							},
							generatePrimaryKeyValue: function (evt, ui) { ui.value = 0; }
						}
					],
					rendered: function (evt, ui) {
						CalcDefaultTelvolgorde();
					}
				});
			} else {
				alert("ERROR:" + response);
			}
		}
	},
	error(xhr, textStatus, errorThrown) {
		SharedFunctionsDAL.ShowUnexpectedError(xhr, errorThrown);
	}
});

function CalcDefaultTelvolgorde() {
	var rowCount = grid.igGrid("rows").length;
	var columnSettings = grid.igGridUpdating("option", "columnSettings");
	if (rowCount === 0)
		columnSettings[5].defaultValue = 0;
	else {
		var dataSource = grid.data("igGrid").dataSource;
		var lastCounter = dataSource._data[dataSource._data.length - 1].Telvolgorde;
		columnSettings[4].defaultValue = lastCounter + 10;
	}
	grid.igGridUpdating("option", "columnSettings", columnSettings);
}

Thanks!