The RTA advised that Airport Motorway Limited (owner of the Eastern Distributor) provided 'incorrect information ... regarding the load bearing capacity of the Eastern Distributor cut and cover roof'. This led to the redesign of the Tunnel Control Centre as two different buildings so as not to exceed load limits.
CCM was clearly not responsible for this change. While it appears that the RTA could have had grounds for an action to recover its additional expenses for this component, but legal advice did not support such action.
This change is also a later development which could not have been foreseen at the signing of the contract.