The case clarifies that where a contract specifies a fixed expiry date, courts should not apply the civil method of time computation unless the contract requires calculation of a period. It also affirms that rectification of a written contract is possible without proof of an antecedent agreement, provided a common intention is clearly established. Importantly, it demonstrates that the enforceability of an on-demand construction guarantee may fall away where a competent tribunal determines that the employer, not the contractor, was in default.