jqgrid dynamic formatting

HTML

<link rel="stylesheet" href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/themes/redmond/jquery-ui.css">
<link rel="stylesheet" href="https://rawgit.com/free-jqgrid/jqGrid/master/css/ui.jqgrid.css">
<script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/jquery-ui.min.js"></script>
<script src="https://rawgit.com/free-jqgrid/jqGrid/master/js/jquery.jqgrid.src.js"></script>
<table id="jqGrid"></table>
<div id="jqGridPager"></div>

JavaScript

var mainGrid = {
  "total": 1,
  "page": 1,
  "pageSize": 20,
  "records": 1,
  "rows": [{
    "id": 7259,
    "var1Name": "2015 Median Age",
    "var1Contents": "MEDIAN",
    "var1IsString": 0,
    "var1IsNumber": 1,
    "var1Value": "44",
    "var2Name": "% '15 HHs",
    "var2Contents": "PERCENT",
    "var2IsString": 0,
    "var2IsNumber": 1,
    "var2Value": "2.07",
    "var3Name": "Wine At Home",
    "var3Contents": "INDEX",
    "var3IsString": 0,
    "var3IsNumber": 1,
    "var3Value": "135"
  }, {
    "id": 7259,
    "var1Name": "2015 Median Age",
    "var1Contents": "MEDIAN",
    "var1IsString": 0,
    "var1IsNumber": 1,
    "var1Value": null,
    "var2Name": "% '15 HHs",
    "var2Contents": "PERCENT",
    "var2IsString": 0,
    "var2IsNumber": 1,
    "var2Value": null,
    "var3Name": "Wine At Home",
    "var3Contents": "INDEX",
    "var3IsString": 0,
    "var3IsNumber": 1,
    "var3Value": null
  }]
};

GridFunctions = {
  formatVariable: function(gridId, columnName, variableValue, variableContents, isNumber) {
    if (variableValue != undefined && variableContents != undefined) {
      switch (variableContents) {
        case "MEDIAN":
          $(gridId).jqGrid("setColProp", columnName, {
            formatter: 'number',
            defaultvalue: null
          });
          $(gridId).jqGrid("setColProp", columnName, {
            formatoptions: {
              thousandsSeparator: ',',
              decimalPlaces: 0
            }
          });
          break;

        case "COUNT":
          $(gridId).jqGrid("setColProp", columnName, {
            formatter: 'number'
          });
          $(gridId).jqGrid("setColProp", columnName, {
            formatoptions: {
              thousandsSeparator: ',',
              decimalPlaces: 0
            }
          });
          break;

        case "RATIO":
          $(gridId).jqGrid("setColProp", columnName, {
            formatter: 'number'
          });
          $(gridId).jqGrid("setColProp", columnName,...