Yes Manish,if Assessee opted for Audit under this section i.e. he do not want to declare 8% profit, than due date for filling ITR will be 30th Sep,but if assessee is eager to declare 8% profit, than due date for filling ITR will be 31st of July.
If section 44AD is applicable than the last date of return filing is 31st July, but if the assesse is willing to declare profit less than 8% than section 44AB will become applicable instead of section 44AD wherein the due date is 30th September.