I had a  symbolfunction that looked like this:
  private function getTrackSymbol(graphic:Graphic):Symbol
         {       
              var symbol:Symbol = nodatasymbol;
              var minpall:Number;
             if (mapvariables.strshowAALayer==MapInitialData.strMinorityField )
                 {
                     if (minoritysetting.boolminoritypercentdefault)
                          minpall = graphic.attributes.MIN_P_ALL; 
                         else
                         {
                          if (minoritysetting.strminoritypercentfields.length > 0)
                          {
                           
                           var tmnumber:Number = 0;
                           if (minoritysetting.strminoritypercentfields.indexOf("t_pop_black_african_amer") > -1)
                            tmnumber += Number(graphic.attributes.t_pop_black_african_amer);
                           if (minoritysetting.strminoritypercentfields.indexOf("t_pop_asian") > -1)
                            tmnumber += Number(graphic.attributes.t_pop_asian);
                           if (minoritysetting.strminoritypercentfields.indexOf("t_pop_hisp") > -1)
                            tmnumber += Number(graphic.attributes.t_pop_hisp);
                            if (minoritysetting.strminoritypercentfields.indexOf("t_pop_haw_PI") > -1)
                            tmnumber += Number(graphic.attributes.t_pop_haw_PI);
                         
                           minpall = (graphic.attributes.persons_pop==0)?0:(tmnumber*100/graphic.attributes.persons_pop);
                          }
                          else
                             minpall = 0;
                          
                         } 
                     }
             else  if (mapvariables.strshowAALayer==MapInitialData.strIncomeField)
                      minpall = graphic.attributes.INC_P_ALL; 
           
               // show on map 
               if (minpall >=0 )
                {
                          if (minpall < commonaasetting.numaabreak1toplimit)//20
                         {
                          symbol =  gsymbol1;//trackinsymbol[0]; 
                        }
                      else if (minpall >=  commonaasetting.numaabreak1toplimit && minpall < commonaasetting.numaabreak2toplimit)
                        {
                         symbol = gsymbol2;//trackinsymbol[1]; 
                         }
                        else if (minpall >= commonaasetting.numaabreak2toplimit && minpall < commonaasetting.numaabreak3toplimit)
                      {
                           symbol = gsymbol3;//trackinsymbol[2]; 
                       }
                        else if (minpall >= commonaasetting.numaabreak3toplimit && minpall < commonaasetting.numaabreak4toplimit)
                        {
                         symbol = gsymbol4;//trackinsymbol[3]; 
                        }
                        else if (minpall >= commonaasetting.numaabreak4toplimit && minpall < commonaasetting.numaabreak5toplimit)
                         {
                          symbol = gsymbol5;//trackinsymbol[3]; 
                       }
                          else if (minpall >= commonaasetting.numaabreak5toplimit )
                       {
                        symbol = gsymbol6;//trackinsymbol[3]; 
                       }
              } 
    
          return symbol;              
        }
The issue is here:
in symbolfunction I could get a value say: minpall = graphic.attributes.MIN_P_ALL; 
and based on user selection I could compute a  value and then compare  the value with the limits to give symbols.
But in classbreak renderer in api 2, I can only mention 
 classValuerenderer.attribute = "MIN_P_ALL";
and compare that attribute value to the limits..
Is there a way to do a computed value comparison with the limits in api 2 (similar to symbol function in 1.3)?