The USPTO has issued a memo to clarify its position on untimely filed petitions to withdraw holdings of abandonment. The clarifications have been developed to prevent delays from inapropriately extending the patent term.
Some Highlights:
UTILITY APPLICATIONS FILED AFTER MAY 29, 2000:
If a petition is not filed within 2-months from the mailing date of the notice of abandonment, any patent term adjustment will be reduced under 37 CFR 1.704(c)(4).
If applicant does not receive the notice of abandonment, any patent term adjustment may be reduced under 37 CFR(a) by a period equal to the time the applicant 'failed to engage in reasonable efforts to conclude prosecution' ... any period of adjustment shall be reduced by the number of days, if any, beginning on the day after the date that is twelve months from the date of applicant’s filing or submission of correspondence with the USPTO for which further action by the USPTO can reasonably be expected and ending on the filing date of a grantable petition to withdraw the holding of abandonment.
UTILITY APPLICATIONS FILED BETWEEN (INCLUSIVE) JUNE 8, 1995 AND MAY 29, 2000:
The USPTO has no authority to grant patent term extension after withdrawing a holding of abandonment unless the application is held abandoned during 1) an interference proceeding; 2) after imposition of s secrecy order; or 3) during a successful appellate review.
...
The clarifications will be added to the MPEP in due course.
For specifics, see the link.