(a) Except as otherwise provided by § 60.4035 or 60.412, before a district or port authority may purchase one or more items under a contract that will require an expenditure of more than the amount authorized under § 60.403(a) for routine purchases or contracts, the port commission of that district or port authority must comply with the competitive bidding requirements or proposal procedures provided by this subchapter or Subchapter O. All bids must be sealed.
(b) The competitive bidding and proposal requirements provided by this subchapter and Subchapter O apply only to contracts for which payment will be made from current funds or bond funds.

(c) In applying the competitive bidding procedures and proposal procedures, all separate, sequential, or component purchases of items ordered or purchased from the same supplier by the same officer, entity, or department, purchased with the intent of avoiding the requirements of this subchapter or Subchapter O, shall be treated as if they are part of a single purchase and a single contract.