Although I agree that your case wil not be scrutinized, the answer your lawyer gave would get you absolutely nowhere. If they conclude that you have filed too early, then you must actaully prove (the burden is now on you) that you had no intention, which is impossible, since you had already filed I-140 and hasd already discussed this with lawyer.
You didn't decide anything "later". You and lawyer decided months ago that you would file AOS at the earliest possible oppurtunity, and you and lawyer carried out that decision. Lawyers shouldn't advise their clients to lie to govt officials.
But, as I've said all along, the chances you will get singled out are infinitessimal. However, if you do get caught, please consult with a more scrupulous lawyer before talking to CIS.