In Thiess Pty Ltd & Anor v Arup Pty Ltd & Ors  QSC 185, (10 July 2012), the Queensland Supreme Court (Applegarth J) was considering the terms of a Collaborative Consultancy Agreement (CCA) in relation to the Airport Link, Northern Busway (Windsor to Kedron) and East-West Arterial Gateway Projects, between Thiess John Holland (TJH) and Parsons Brinkerhoff Australia (PBA). TJH had engaged PBA as consultants for the design of the project. His Honour was asked to resolve whether, under the CCA, certain values of multipliers specified in the CCA were values agreed between the parties or were subject to audit by the Collaborative Agreement Auditor. His Honour concluded in favour of PBA, that the values were agreed between the parties and not subject to audit by the Collaborative Agreement Auditor.
His Honour considered the interpretation principles, reasoning as follows:
The proper interpretation of the contract is not determined in this case simply by competing contentions about which interpretation is the “more commercially sensible” construction. It is determined by the words of the agreement that were chosen by the parties, and the structure of Schedule 7.
His Honour reasoned in relation to the request for rectification:
These and other authorities appear to support the following propositions:
- The actual intention of each party is relevant in deciding whether they had the alleged common intention.
- The actual intention must have been disclosed.
- In determining whether there was the alleged common intention and the terms of the “prior consensus”, a Court is not confined to communications between the parties and their conduct from which the relevant intention may be inferred. Evidence of their subjective intention, including statements about their understanding of what was agreed, is admissible, and in some circumstances may be decisive.
- Where, however, the evidence given by a party about his or her subjective intention is inconsistent with the terms of their correspondence and/or conduct it may carry little weight.
- The existence or otherwise of a “common intention” (or prior consensus or prior concluded agreement) is determined on the basis of an objective assessment of the parties’ communications and conduct. Whilst evidence from a party about his or her subjective intention is admissible as to whether the alleged consensus was reached, the question of whether such a consensus existed and continued involves an objective assessment. The authorities suggest that the test is what an objective observer would have thought the intentions of the parties to be. In this regard, it is not the inward thoughts of the parties which matter but whether the alleged intention has been objectively manifested. To adopt the words of Street J, the intention on each side must be manifested “by some act or conduct from which one can see that the contractual intention of each party met and satisfied that of the other. On such facts there can be seen to exist objectively a consensual relationship between the parties.”
TJH had argued that there was a reasonable expectation that the multiplier was a genuine or reasonable estimate and that PBA had been acting in good faith in originally proposing them, and further, that it had a reasonable expectation of an auditor’s examination, and that if there was to be no such examination PBA would have disclosed this to TJH. His Honour summarised the cases:
 Silence or non-disclosure of information can be misleading or deceptive in various circumstances….. Whether silence constitutes misleading or deceptive conduct depends on all the relevant circumstances, and it is dangerous to essay any principle by which they might be exhaustively defined. However, “unless the circumstances are such as to give rise to the reasonable expectation that if some relevant facts exists it would be disclosed, it is difficult to see how mere silence could support the inference that the fact does not exist” …… Asking whether a reasonable expectation of disclosure exists is an aid to characterising non-disclosure as misleading or deceptive and has been described as a practical approach to the application of the prohibition in s 52.
 Sometimes a reasonable expectation of disclosure will not exist because parties to a commercial negotiation are not expected to disclose information which is confidential, and the starting point for their negotiations is the caveat emptor doctrine. On other occasions, a reasonable expectation of disclosure will exist because of the nature of the relationship, or because positive conduct or statements in the course of negotiations imply that a certain fact or matter exists or does not exist. A failure to qualify a statement made earlier in negotiations may be misleading or deceptive in the circumstances. Where, however, this is not the case, the reasonable expectation of disclosure of a certain fact must be found elsewhere. In this case, TJH seeks to source it by reference to the negotiation and entry into the Pre-Bid Agreement and the parties’ subsequent negotiations in relation to the commercial framework and the terms of Schedule 7, as pleaded in paragraph 85 of the second further amended defence and counterclaim. Whether conduct is misleading or deceptive or likely to mislead or deceive must be assessed on the basis of these facts and all the relevant circumstances.
Ultimately, His Honour concluded that there was no misleading and deceptive conduct in this instance, concluding that PBA should have the declaratory relief it sought.