Audit in 10B

we have an NGO registeted under 80G. Previous year we filled Income Tax return and audit in 10 B. In previous year we made surplus above basic exemption limit and took deduction u/s 11 . Now this year we have deficit. Now what is right to do audit in 10 B for which last date is 31st sep, or we have to file normal income tax return for which last date is 31st July.