Monitor-Room Issue

Well, I was about to get my self a pair of S3A but I’ve talked with a professional acoustic adviser and he told me that double 7.5" woofer monitor is not fit my control room and it's a bad bad choice to my room. My room is 6.26 M Long - 3.38 M wide and 2.40 High. He told me that anything bigger than 6" will make an unbalanced boomy sound because freq waves need space to develop and monitors need a lot of space, and it's a matter of physics. I just want to mention that the room is well acoustically treated including bass traps, ceils foams and Auralex Wedgies Acoustic Foams on the sidewalls. I don't know what to think - I’m all confused. Should I end up with a smaller monitor or not? Does bigger woofer needs a bigger room? Does lower freqs needs bigger room? Oh, and the money is not a priority. Thanks.