Perm denied without audit due to less than 60 months experience,but we have included 60 months experience letter and CO did't see the previous exp

It could be an error on the part of the DOL. It is difficult to assess where the error occurred without actually have an opportunity to review the filing and denial. You should be consulting your attorney. The attorney who has handled the matter and filed the request for reconsideration is in the best position to address your questions. If, however, you wish to have a second opinion, you should obtain a copy of the file and schedule a consultation with an attorney. In the interim, you can read more about PERM at http://myattorneyusa.com/employment-immigration.