Just a question about mRender

Hi. I just want to ask some question about 'mRender'.
For some fields I specify it as a function to return some formatted content. Something like this

		    "aoColumns": [
				{ 
					"mData": "createdDate",
					"mRender": function ( data, type, full ) {
					        console.log("i_"+full.id);
						var curDate = new Date(data);
						if (curDate.toDateString() == new Date().toDateString()) {
							return curDate.getHours()+':'+curDate.getMinutes();
						} else {
							var day = d_names[curDate.getDay()];
							return '<abbr title="'+day+'">'+day[0]+'</abbr> +curDate.getHours()+':'+curDate.getMinutes();
						}
					}
				},

So, when I have, for example 2 records(actually I have 8 records :-)) with ids 42 and 25, I see during table rendering in my firebug console output like this:

i_42
i_42
i_25
i_25
i_42
i_25

So I made a conclusion that during rendering of a table the 'mRender' function is called 3 times for each record.
My simple question is. Is that an optimal way of doing it? mRender (as I understand) gives us a final content to be placed into <td>. Why we should call it three times?

Sorry, I did not dig deep into the code of the dataDables. Maybe it is a right way of doing it. Maybe it does not matter much. Anyway, I do not have a lot of records to be this an performance issue for me. I just asking. Also here is my whole cnfig

	    	var table = this.$el.dataTable( {
	    		"sDom": "<'row-fluid'<'span6'l><'span6 jqtReload'>r>t<'row-fluid'<'span6'i><'span6'>>",
	    		"bPaginate": true,
		        "bFilter": true,
		        "bSort": false,
		        "bInfo": true,
		        "bAutoWidth": false,
				"bProcessing": true,
				"sScrollY": "185px",
				"bScrollCollapse": true,
		    	sAjaxSource: "",
		        sAjaxDataProp: "",
		        fnServerData: function( sSource, aoData, fnCallback ){
		        	fnCallback(_that.collection.toJSON());
		        },
		        "aLengthMenu": [[3, 5, 8, 10, -1], [3, 5, 8, 10, "All"]],
		        iDisplayLength: -1,
		        "aoColumns": [
					{ 
						"mData": "createdDate",
						"mRender": function ( data, type, full ) {
							console.log("i_"+full.id);
							var curDate = new Date(data);
							if (curDate.toDateString() == new Date().toDateString()) {
								return curDate.getHours()+':'+curDate.getMinutes();
							} else {
								var day = d_names[curDate.getDay()];
								return '<abbr title="'+day+'">'+day[0]+'</abbr> '+curDate.getHours()+':'+curDate.getMinutes();
							}
						}
					},
					{ 
						"mData": null,
						"mRender": function ( data, type, full ) {
					    	if (full.toAddress === undefined) {
					        	return full.fromAddress;
					      	} else {
					      		return full.fromAddress + ' <i class="icon-arrow-right"></i> ' + full.toAddress;
					      	}
						}
					},
					{ "mData": "creator" },
					{ "mData": "region" },
					{ "mData": "state" },
					{ 
						"mData": "statusId",
						"mRender": function ( data, type, full ) {
							return '<i class="icon-ok-sign"></i>';
						}
					}
				]
			} );

Hmm. When setting "bFilter": false, it is only 2 times for each record.