         label         : "Price is volatile"
         itemClass     : KDOnOffSwitch
         defaultValue  : data.priceIsVolatile
-        callback      : =>
-          enabled = @inputs.priceIsVolatile.getValue()
-          do @fields.feeAmount[if enabled then 'hide' else 'show']
+        callback      : @bound 'priceVolatilityChanged'
 
     if options.showOverage
       options.fields.overageEnabled =

        priceIsVolatile
      }

  handleSubscriptionType: ->
    subscriptionType = @inputs.subscriptionType.getValue()
    if subscriptionType is 'single'
      @inputs.perMonth.hide()
    else
      @inputs.perMonth.show()
      @inputs.perMonth.updatePartial "/ #{subscriptionType}"

        type      : "submit"
      cancel      :
        cssClass  : "modal-cancel"
        callback  : => @emit 'CancelRequested'

    options.fields ?=

