CSC's director believed Watts & Hughes had chosen to treat the claim as received by the due date.
When he did not receive a payment schedule or payment by late March, he instructed lawyers to serve a statutory demand on Watts & Hughes for $306,077.
CSC also entered the site and dug up parts of the carpark.
Watts & Hughes, on the other hand, said it had elected to treat the payment claim as being received during March and therefore no payment schedule or payment was due until late April.
The head contractor applied for the High Court at Wellington to set aside the demand.
But Associate Judge Warwick Smith concluded that Watts & Hughes was required to communicate its decision on the payment claim and that it had not done so.
"The result of that finding is that the amount of payment claim No6 did become due and owing by Watts & Hughes to CSC on 27 March 2014, and Watts & Hughes had no arguable defence to the statutory demand. The application to set aside the statutory demand is accordingly refused," the judge said.
The head contractor then took the matter to the Court of Appeal, arguing the payment claim was invalid because it was late.
The Court of Appeal, last year, rejected this.
Watts & Hughes also argued that because CSC dug up part of the carpark it could not submit a claim because it had undone the work. However, that argument was also rejected.
In its commentary on the case, released last week, law firm Chapman Tripp said the judgment confirmed parties must clearly communicate the choices they make in contractual elections.
"Otherwise, the court may take the matter out of the electing party's hands," the firm said.