Query on section 54f of income tax

It is a well known fact that u/s 54f if the assessee is unable to purchase a house then he can submit the unutilised amount in CGAS Account before the filling date.

Now my query is that for most of the people the filling date is 31st july but for a person who is liable to tax audit and his filling date being 30th september then for that particular assessee what is the date he needs to submit the money into CGAS account.

PLEASE REPLY ASAP WITH SUFFICIENT REFERENCES.

THANK YOU