you can use groupOption event to switch between 2 column aggregates and all column aggregates.
groupOption: function(evt, ui){
var newPivot = this.option('groupModel.pivot');
//pivot turned on
if( newPivot && !ui.oldGM.pivot ){
this.getColModel().forEach(function(col){
if(col.dataIndx != "proBudget" && col.dataIndx != 'proOverUnder' ){
col.summary = null;
}
})
}
//pivot turned off
else if( !newPivot && ui.oldGM.pivot ){
this.getColModel().forEach(function(col){
col.summary = {type:'all'};
})
}
//debugger;
},