(a) A judicial proceeding for breach of any obligation arising under section 4-113 or 4-114 must be commenced within six years after the cause of action accrues, but the parties may agree to reduce the period of limitation to not less than two years. With respect to a unit that may be occupied for residential use, an agreement to reduce the period of limitation must be evidenced by a separate instrument executed by the purchaser.
(b) Subject to subsection (c), a cause of action for breach of warranty of quality, regardless of the purchaser's lack of knowledge of the breach, accrues:
(1) As to a unit, at the time the purchaser to whom the warranty is first made enters into possession if a possessory interest was conveyed or at the time of acceptance of the instrument of conveyance if a nonpossessory interest was conveyed; and