Sec. 4. As used in this chapter, "date of substantial completion" means the earlier of:
(1) the date upon which construction of an improvement to real property is sufficiently completed under a contract of construction, as modified by any additions, deletions, or other amendments, so that the owner of the real property upon which the improvement is constructed can occupy and use the premises in the manner contemplated by the terms of the contract; or
(2) the date of the first beneficial use of the improvement to real property or of any portion of the improvement.