Football Conference chairman Brian Lee said he is comfortable with the process that led to points deductions for Oxford, Crawley, Mansfield and Bognor.
Lee backed the findings of an internal review saying it was just coincidence that four clubs had ended up fielding unregistered players in one season.
"Everyone thinks there was a whitewash," he told BBC Oxford. "If there was we would have said so."
Oxford were punished because Eddie Hutchinson was not registered properly.
They were docked five points after a 'random check' system took three months and 13 matches for anyone to identify the administrative error.
Lee admitted that team sheets have been changed in the last few months in the wake of the saga but described this as a "tightening" of procedures rather than a change.
He added that he has been told by the Conference office that they have found no other incidents of unregistered players being used.
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