Fifa’s call for its members to embrace reform as Friday’s presidential election looms has been undermined by its own appeal committee, which has reduced bans for Sepp Blatter and Michel Platini because of their “services to football”.

The Fifa appeal committee ruled that the bans handed down to the pair by the ethics committee in December over a £1.3m “disloyal payment” from the disgraced Fifa president to the Frenchman were too onerous and should be reduced from eight years to six years.

The decision means that neither Blatter, the Fifa president for 18 years, nor his one time heir apparent will be able to stage a Lazarus-like return before Friday’s extraordinary congress. But the reasoning for the decision by the appeal committee will be seen as an embarrassment at a time when Fifa is trying to implement a string of reforms that it hopes will maintain its victim status in the eyes of the US Department of Justice and the Swiss Attorney General.

The appeal committee, chaired by Larry Mussenden, ruled that some “strong mitigating factors” were not taken into account by the ethics body. “In this sense, among others, the appeal committee considered that Mr Platini’s and Mr Blatter’s activities and the services they had rendered to Fifa, Uefa and football in general over the years should deserve appropriate recognition as a mitigating factor.”

The investigatory arm of the ethics committee had itself challenged the eight‑year ban, believing that the 2m Swiss francs payment was corrupt and actually merited a life ban. Platini and Blatter have denied wrongdoing over the secret “gentleman’s agreement” under which the former received the equivalent of £1.3m in 2011 for work undertaken as a Fifa adviser between 1999 and 2002. Platini and Blatter have both confirmed they will appeal again to the court of arbitration for sport, with Blatter describing his continued ban as “insulting” and “shameful”. He added: “I’m deeply disappointed by the Fifa appeal chamber and the next step is going further to Cas in Lausanne.”

In a statement, Platini said: “The charges against me are baseless, built from the ground up and surreal in view of the facts and the explanations I gave during the hearing. I will go through all the possible appeals, starting with Cas. I will go to the end of my fight to show I’m innocent.”

As Friday’s election teetered on the brink of farce, the Cas refused a request from the Jordanian Prince Ali bin al-Hussein to force Fifa to use transparent voting booths or postpone the election until it could rule on the matter.

The Cas threw out the complaint, despite Ali saying earlier in the day that he had been told by associations from at least three confederations that pressure had been put on them to prove who they had voted for in the supposedly secret ballot.

Ali had the special booths flown in overnight but they will now sit unused outside the Fifa congress venue as a very literal challenge to Fifa’s vows over transparency. The Jordanian, who is third favourite behind Sheikh Salman bin Ebrahim al-Khalifa and Gianni Infantino, insisted he would not pull out. “I’m in there until the end and I’m there to fight for the future of football. I’m very optimistic. But again it has to be the right process. I will go through with it for sure.”

As Infantino, the Uefa general secretary, insisted he was optimistic of winning what is expected to be a close race that will go beyond the first round of voting, the favourite, Sheikh Salman, said Fifa’s 209 members should trust him. “If they don’t trust me then they shouldn’t vote for me. And if they trust me, they will,” he told CNN.