           else
             # iterate over parcel instances
             _.each _.keys(deliveryDiff.parcels), (parcelIndex) ->
-              if parcelIndex != '_t'
+              if parcelIndex  isnt '_t'
                 parcelDiff = deliveryDiff.parcels[parcelIndex]
 
                 if _.isArray parcelDiff

    if deliveriesDiffs
      # iterate over returnInfo instances
      _.each _.keys(deliveriesDiffs), (deliveryIndex) ->
        if deliveryIndex != '_t'
          deliveryDiff = deliveriesDiffs[deliveryIndex]
          if _.isArray deliveryDiff
            # delivery was added

    if returnInfoDiffs
      # iterate over returnInfo instances
      _.each _.keys(returnInfoDiffs), (returnInfoIndex) ->
        if returnInfoIndex isnt '_t'
          returnInfoDiff = returnInfoDiffs[returnInfoIndex]
          if _.isArray returnInfoDiff
            # returnInfo was added
