While the prosecutors agreed to the terms of Mr. Perone's guilty plea in March, they now say that the recommended penalty calculated by the federal sentencing guidelines is "woefully inadequate".
The charge carries a recommended penalty of up to a year in jail, but there is no category in federal sentencing guidelines for assault with a pie in a disposable aluminum tin.
However, she added, that does not negate the recommended penalty for past reporting problems.
In a landmark decision, the United States Sentencing Commission voted last month to lower the recommended penalty for federal drug crimes by about 17percentt.
After reviewing complaints, she may recommend penalties.
It could drop the whole matter, recommend penalties or hold more meetings.
The agency that investigated Mr. Bibb's actions, an arm of the judiciary, can recommend penalties as serious as disbarment.
The Transportation Ministry said it was studying the possibility of recommending penalties for Mitsubishi because of the cover-up, including criminal prosecution.
While it is unlikely that the commission would rescind its approval of the merger, it could recommend penalties as part of a settlement.
If it recommends penalties, the fight could move to court or end, as these often do, in a settlement and fines.
