Thanks guys,
this formula works great!! ACC: IIf(IsNull([Allocated Overwidth Charge Cost])=True,0,[Allocated Overwidth Charge Cost])+IIf(IsNull([Allocated Stop Charge Cost])=True,0,[Allocated Stop Charge Cost])+IIf(IsNull([Allocated Tarp Charge Cost])=True,0,[Allocated Tarp Charge Cost])...