Construction on the $450-million arena is slated to begin early next year.
John Karvellas, executive vice-president of the Katz Group, didn't say what the revised cost would be, but said the Oilers would pay their fair share for any costs over the $450 million.
Councillor Kim Krushell, a longtime supporter of the project, was asked if council was "blindsided" by the Katz Group request for extra funds.
Another $100 million is being sought from the province, although Premier Alison Redford's government is adamant no tax dollars will go to private ventures.
Mandel said that they're getting closer to solving that problem.
"We've been working with the province on various programs and we believe they're getting close to coming up with a solution that would deal with the realities of every town and village and city … coming up with funds for facilities like the arena project," he said.
Council has already been told that the city's ultimate contribution will far exceed $125 million.
Officials estimate that when borrowing and land purchase costs are factored in, the number becomes $305 million. Another $57 million will be spent for a light-rail transit extension to the rink, a pedestrian corridor and an above-ground walkway over the main avenue in front of the building.
A proposed community rink would add another $21 million. The city would also pay Katz $20 million over 10 years to advertise through his team. It's not clear what form that advertising would take.
The base number itself is already rising.
In July, councillors were told revised estimates have boosted the original $450-million figure to $485 million, prompting designers to look at ways to cut back on some of the amenities, like some of the concession stands and the Oilers retail store.
The Oilers would pay their $100 million in instalments: $5.5 million in annual rent for 35 years, plus interest, for a total of $186 million.
The team would pay to operate the building and keep the profits for 11 months out of the year.
Katz would retain the naming rights for the building. Comparable estimates put that at $1 million a year.
The deal would bind the team to staying in Edmonton for the next 35 years.
The proposed rink is a futuristic structure of wavy lines and curves done over in zinc, masonry and glass in the broad shape of an oil drop.
There would by 18,400 seats along with clubs and bistros, even a space to hold beach volleyball tournaments, along with underground parking.
The city is banking that the arena will be a catalyst for more retail and housing.Continue reading below
Built in 1974, it's the second-oldest rink in the NHL. The oldest is the arena where the New York Islanders play.
The Oilers are the only NHL team that doesn't get non-hockey-related revenue from its building.