jqGrid applying sort from known values not working - jqgrid

Question

I have a jqGrid and want to apply user's sort values after it loads. These values are saved and retrieved in jquery cookies. I am storing data in cookies because user will go to another url and come back which initiates page load and they want to be in same spot they left.
I have a loadPreferences function being called within loadComplete.
See code snippet below(I left several jqrid properties out to keep posting short).
// Set up the jquery grid
$("#jqGridTable").jqGrid(
{
// Ajax related configurations
url: jqDataUrl,
datatype: "json",
mtype: "GET",
autowidth: true,
// Configure the columns
colModel: columnModels,
// Grid total width and height
height: "100%",
// customize jqgrid post init
gridComplete: function()
{
CRef.updateJqGridPagerIcons("jqGridTable");
},
// Default sorting
sortname: "LastName",
sortorder: "asc",
sorttype: "text",
sortable: true,
jsonReader:
{
root: "rows",
page: "page",
total: "total",
records: "records",
repeatitems: false,
userdata: "userdata"
},
loadComplete: function (data)
{
if (boolPreferencesLoaded == false)//page level variable
{
boolPreferencesLoaded = loadPreferences(this);
$("#jqGridTable").trigger("reloadGrid");
}
isGridSorting(this, false);
}
...the rest of grid properties...
and in the function call(which is located in another js file), I have...
function loadPreferences(gridId)
{
if (typeof $.cookie("sortCol") !== "undefined")
{
$(gridId).jqGrid("sortGrid", $.cookie("sortCol"), true, $.cookie("sortOrd"));
}
return true;
}
function isGridSorting(gridId, sorting)
{
$.cookie("sortCol", $(gridId).jqGrid('getGridParam', 'sortname'));
$.cookie("sortOrd", $(gridId).jqGrid('getGridParam', 'sortorder'));
$(gridId).jqGrid('setGridParam', { postData: { isSorting: sorting } });
}
My problem is when I go to apply them on page load(with jqGrid specified above), it does not exactly work. The icon moves to correct column and the arrow is pointing in correct direction, but the data in column does not sort.
I know there are a lot of posts dealing with similar issues, but not able to get solutions to work. What I am trying to do seems to easy, but it's driving me nuts. If you respond, please make comment easy to understand. Thank you.