mdata with function on multiple columns

Hello,
I need to individually change rendering of three columns values adding span tags and leave original values intact for sorting purposes.
So I tried to apply mData functions on multiple columns, like this:

{ 'aTargets': [ 2 ],  
                                'mData'    : function(source, type, val) {
                                                if ('set' === type) 
                                                {
                                                    source[2] = Number(val);
                                                    source.rendered = '<span class="indicator"><span title="' + ((0 === source[2])? realTimeMonitor.fault0Title : (source[2] + ' ' + realTimeMonitor.fault1Title)) + '" class="' + ((0 === source[2])? 'green' : 'red') + '"></span></span>';
                                                    return;
                                                }
                                                else if('display' === type || 'filter' === type) 
                                                {
                                                    return source.rendered;
                                                }
                                                
                                                return source[2]; }
                              },
                              { 'aTargets': [ 3 ],
                                'mData'    : function(source, type, val) {
                                                if ('set' === type) 
                                                {
                                                    source[3] = Number(val);
                                                    source.rendered = '<span class="indicator"><span title="' + ((0 === source[3])? realTimeMonitor.threshold0Title : (source[3] + ' ' + realTimeMonitor.threshold1Title)) + '" class="' + ((0 === source[3])? 'green' : 'red') + '"></span></span>';
                                                    return;
                                                }
                                                else if('display' === type || 'filter' === type) 
                                                {
                                                    return source.rendered;
                                                }
                                                
                                                return source[3]; }
                              },
                              { 'aTargets': [ 4 ],
                                'mData'    : function(source, type, val) {
                                                if ('set' === type) 
                                                {
                                                    source[4] = Number(val);
                                                    source.rendered = '<span class="indicator"><span title="' + ((0 === source[4])? realTimeMonitor.network0Title : ((1 === source[4])? realTimeMonitor.network1Title : realTimeMonitor.network01Title)) + '" class="' + ((0 === source[4])? 'grey' : ((1 === source[4]) ? 'green' : 'red')) + '"></span></span>';
                                                    return;
                                                }
                                                else if('display' === type || 'filter' === type) 
                                                {
                                                    return source.rendered;
                                                }
                                                
                                                return source[4]; }
                               }

My problem is that third mData definition somehow overwrites the previous ones so my table displays third column rendering in the previous ones; moreover only the first columns is sorted correctly.

Could you address me to the mistake I'm doing?

Thanks in advance for your kind answers.