Barton was on Wednesday handed a 12-match ban for his dismissal and violent reaction at the Etihad Stadium on May 13, when City beat QPR 3-2 to win their first league title for 44 years.
Tevez appeared to strike out at Barton initially, and Dean, via video link, told the regulatory commission that it was a red-card offence which had gone unnoticed.
In the report, which is signed by commission chairman B.M Jones, it is stated that: "Mr Dean was questioned about the 'Tevez' incident for which Mr Barton was dismissed. It was confirmed that neither the referee nor the assistant saw the alleged incident of Mr Tevez striking Mr Barton although Mr Barton immediately made representations to Mr Dean that is what happened, and such comments by Mr Barton can be clearly seen in the video.
"The commission accept that Mr Barton was aggrieved by the action of Mr Tevez and Mr Dean confirmed that had the incident been seen by the officials as shown by the clip supplied by Mr Barton, it would have been an automatic red card.
"The commission find that this does not however excuse the subsequent action by Mr Barton in relation to Messrs Kompany or Aguero."