Listen to your attorney. You are in removal proceedings which means only the Office of Chief Counsel can agree to prosecutorial discretion. That's a different process than the new deferred action process for child arrivals announced by the President on June 15. You can also apply for the deferred action if you qualify. Your chances are not hampered by asking twice or asking for benefits through two different processes. Finally, your attorney is supposed to discuss the options with you and your obligation is to decide which option you prefer.
The answer provided here is general in nature and does not take into account other factors that may need to be reviewed for a more precise answer. You should consult with an immigration attorney before taking any action. The answer here is not intended to create an attorney-client relationship.
Listen to your attorney. He was simply using the available options before 8/15 and with deferred action now a possibility he is discussing that option as well.
DISCLAIMER: This answer does not constitute legal advice and no attorney client relationsip has been, or will be, created until a valid engagement agreement is signed. No duty arises from this posting. Answers posted here are general and made with limited knowledge of the actual facts of your case. Always speak with an attorney licensed to practice law in your jurisdiction if you wish legal advice specific to your case.
The request through OCC and the request through USCIS are two different processes. Starting tomorrow, the 15th, you'll have the opportunity to ask through USCIS - regardless of if OCC has made a decision in your case or not. Your attorney seems to be keeping all avenues of relief open for you.
This general advice does not create an attorney-client relationship.