SPServices/Json - "Requested Unknown Parameter" Missing JSON Column

My JSON Code sometimes skips columns, due to the Source tables not being filled out completely. Null fields aren't returned in my web service.
SPservices only brings back the columns that are not null.

myJavascript:

  $().SPServices({
	                operation: "GetListItems",
	                async: false,
                    webUrl: "http://mywebsite.com",
	                listName: listA, //EDIT HERE// This is the Name of the Sharepoint List you want to Retrieve
	                completefunc: function (xData, Status) {

 myJson = $(xData.responseXML).SPFilterNode("z:row").SPXmlToJson({
	                        mapping: {
	                            ows_LinkFilename: { mappedName: "Filename", objectType: "Text" },
	                            ows_Title: { mappedName: "Title", objectType: "Text" },
	                            ows_Unit_x0020_NO: { mappedName: "UnitNo", objectType: "Lookup" },
	                            ows_Area: { mappedName: "Area", objectType: "Lookup" },
	                            ows_Complex: { mappedName: "Complex", objectType: "Lookup" },
	                            ows_DocType: { mappedName: "DocType", objectType: "Lookup" }
	                    	 }, // name, mappedName, objectType
                                   includeAllAttrs: false
	                    });
	                    //alert(myJson[0]["Title"]);//returns the value
	                    return myJson
	              
	                }// End of completefunc
	            }); //End of SPServices

Console Info:

Row1 Debug: Object {Filename: "Test Folder", Title: "Test Folder"}
Row2 Debug: Object {Filename: "007316.pdf", Title: "7V-316", UnitNo: Object, Area: Object, Complex: Object…}

What are my options?
Does the data have to be absolutely consistent each time?
I'm doing a webservices request for XML, tranforming to JSON and then posting to Datatables.
Can I turn off the debug... and just skip the Datatables Error message.

Or should I go back to my original webservice and see If I can change SPservices? What's the best practice or proper approach on this?