This is in addition to claims for inefficiencies and product defects, as well as damages for breach of contact – capped at £6 million – after the Darlington firm walked off the site in August 2004.
The two firms returned to court for their latest trial yesterday morning, which will decide exactly how much the pair owe each other.
In his opening statement, Roger Stuart QC, for Multiplex, said "they are over £7 million too high" in relation to the interim payment made to CBUK. The fee was for work meant to be completed before February 15, 2004.
Another major point in the case will be determining whether Multiplex owes monies for work completed between the interim payment date and August 2, the date when CBUK repudiated its contract.
But Mr Stuart said there were no figures available as to how much steel had actually even been fabricated and provided by CBUK.
He said: "There is no definitive figure either for how much steel was put up pre-February 15 or on subsequent dates.
"Neither is there a figure for the total amount of steel contained within Wembley, neither a figure for the total amount of steel as a consequence of variation."
Beginning his opening statement for CBUK, Adrian Williamson QC admitted there was "little common ground between the parties" on figures owed.
He said: "Within Multiplex’s own documents [there was] no reason to suppose the repudiation cost them anything at all."
It is expected the trial, being heard by Mr Justice Jackson, will last until the end of April.
At the original trial in 2006, the court found CBUK had breached its contract when it walked off site.
Mr Williamson will conclude his opening statement this morning.