Print out this post for user friendly preparation and take to the employer's immigration attorney. They should be able to answer this. Hire an independent immigration attorney for a consultation, as an alternative.
NYC EXPERIENCED IMMIGRATION ATTORNEYS www.myattorneyusa.com; email: firstname.lastname@example.org; Phone: (866) 456-8654; Fax: 212-964-0440; Cell: 212-202-0325. The information contained in this answer is provided for informational purposes only, and should not be construed as legal advice on any subject matter.
Cannot advice without knowing why you had a month difference and why the employer did not file for extension before August.
Business Immigration Attorney with 17 years of immigration law experience. Call 800-688-7892 or visit www.ImmigrationDesk.com. Law Office of Anu Gupta. The advice suggested here is for general information only and not to be construed as legal advice.
It is hard to assess the likelihood of success based in this information. I would ask the attorney that filed it for you and listen to their assessment. The fact that you filed a nunc pro tunc petition will work in your favor with later filings, which doesn't mean that the gap in status won't have negative consequences.
Whether the petition will be approved depends on the merits of the case. Without reviewing the petition and considering the reason for applying "nunc pro tunc", it is not feasible to answer your question.
This response is general in nature and cannot be construed as legal advice, given that not enough facts are known. Any comments offered on Avvo are of a general nature only, and are not meant to create an attorney-client relationship. If you would like additional information based on this response, please contact my office at 510 657 7665 or 415 902 0832 to schedule a consultation.