Section 188. Service charge based on quantity

No person shall impose a
  service charge which is based upon quantity  in  excess  of  the  actual
  quantity   of  any  commodity  or  article  serviced.  Nothing  in  this
  provision, however, shall prohibit the person or persons  rendering  the
  service from establishing a minimum charge therefor; such minimum charge
  to  apply to all quantities up to and including a fixed limit regardless
  of the actual weight or measure of the commodity involved.  In the event
  of the establishment of a minimum charge, the dispenser of  the  service
  shall  inform  the  person  receiving  the  service, by advertisement or
  otherwise, of the terms of such minimum charge.