To be EB2, you must have -- AND THE JOB must require -- either a MS or a BS and 5 years experience.
You have no trouble in your personal quals of course. The difficulty is sometimes the job requirements. The comapny, in its PERM application cannot just 'say' they needed a guy with a BS and 5-year exp. It has to be borne out by the job description. So, sometimes, EB2 is denied late in the game at the I-140 stage.
Now, having said that, there is so much advantage for you to file Eb2 (unless you are born in CH in IN) that I would definitely be giving it a shot.