OAKLAND — The plan Floyd Kephart has been pitching to get a new Raiders stadium built in Oakland appears to have one heretofore hidden flaw — it violates key terms the team insisted upon in April.

In discussing his latest financing plan for the Coliseum City mega development last week, Kephart once again recommended that the estimated $400 million shortfall for a $900 million Raiders stadium should be closed primarily through issuing bonds backed mostly by revenue generated at the future stadium.

Kephart, the city’s handpicked financial partner for Coliseum City, said the revenue would come from “nongame events, a portion of naming rights or things like that.”

What he didn’t say was that the Raiders had already made clear to him in a three-page letter, obtained by this newspaper, that they insisted on keeping all stadium revenue to help with their $500 million contribution to the stadium, including the repayment of an anticipated $200 million NFL loan.

“Simply put, the ‘terms required for the Raiders to commit to remaining in Oakland’ are a plan that fills that funding gap without stripping revenues from the stadium and preserves the current level of surface parking (for tailgating),” Raiders President Marc Badain wrote to Kephart on April 28.

He added that “all revenues from the stadium must be retained by the Raiders.”

For a team that has said little about its stadium limbo and possible return to Los Angeles, the letter offers perhaps the clearest insight into what it will take to keep the Raiders in Oakland as well the team’s frustration with the city, Alameda County and Kephart.

The Raiders and Kephart declined to comment for this story. When asked about it by KCBS Radio on Wednesday, Kephart responded via email to the station that the Raiders letter had been misinterpreted and “taken totally out of context.”

However, Assistant City Administrator Claudia Cappio, who has led recent stadium talks, acknowledged “a conflict with the Raiders may exist” if Kephart is counting on stadium revenues to finance the project. And Alameda County Supervisor Nate Miley said he was unaware of the Raiders budging from their stance on surface parking and stadium revenue.

“I think there is a disconnect between what Floyd Kephart is offering and what the Raiders are looking for,” he said.

The fact that Kephart’s recommended financing plan lacks the Raiders’ two conditions for a stadium deal — the number of surface parking spaces would be roughly halved to make room for new homes, shops and offices — doesn’t necessarily doom the team’s future in Oakland, but it could spell the end for Kephart’s role in the project.

“This has been a waste of time,” said Andy Dolich, a sports business consultant and former executive for three Bay Area teams. “Why have the city and county spent so much time, effort and money pursuing something that was dead in April?”

Kephart, a 73-year-old finance professional, emerged last October as the point person for Coliseum City — a $4 billion project that would transform Oakland and Alameda County’s 120-acre Coliseum site into a destination center with new sports facilities, 3,500 homes, a hotel, shopping center and high-rise office buildings.

Unlike the two major development firms that preceded him, Kephart put money into trying to make the project work and got Alameda County to the negotiating table. But his initial financing plan in June, which also called for the issuance of bonds backed by future stadium revenue, was widely panned as primarily benefiting his still-unnamed investors.

Speaking on condition of anonymity, several local officials doubted that Kephart’s contract to pursue the deal would be renewed when it expires on Sept. 24. Meanwhile, his role has been reduced from the point person negotiating with the Raiders to merely a potential investor advising the public agencies about how a deal could work.

Kephart told KFWB Radio in Los Angeles last week that Oakland asked him to stop talking with the Raiders — a claim disputed by Cappio. But the April letter from the Raiders shows that team officials didn’t trust him to act as an intermediary with local officials.

“It is inappropriate for a third party to speculate on behalf of the Raiders and represent the status of negotiations that have not occurred,” Badain wrote.

Badain also aired his frustration with local officials and the Coliseum City plan, which he said was supposed to provide private money to help the Raiders build a new stadium.

He claimed Oakland officials, under former Mayor Jean Quan, had offered the Raiders free land, promised up to $144 million for infrastructure improvements and identified “private developers who they claimed would fill the gap that remained … in exchange for acquiring development rights around the stadium.”

But even though the Raiders offered to sell a limited share in the team to a developer “willing to fund the gap,” Badain noted that the first two private development groups weren’t willing to contribute any capital to the stadium project, and Kephart at the time also hadn’t “committed any capital.”

Kephart’s latest proposal includes buying much of the Coliseum land for more than $100 million. After originally wanting the city and county to reinvest most of that money into new parking garages, he said the money would be unencumbered and could go to help pay for a stadium.

Since April, the Raiders have had direct stadium talks with the city, which insists it never offered the team free land. While the Raiders are continuing to pursue a stadium proposal with the San Diego Chargers in the Los Angeles suburb of Carson, there is no guarantee that the NFL will greenlight the project and let the team return to Southern California. The St. Louis Rams have a competing Los Angeles-area stadium plan.

Contact Matthew Artz at 510-208-6435.