I recall a post last year by someone who attempted to submit a Secondary prematurely, and they got an email 'yelling' at them that, ~"Contrary to what may have been posted on a popular med school application support site, it is not acceptable to submit the Secondary application without invitation." I don't know that this is universally true, but it makes one think twice about it. The Pre-Med Allo School Specific threads from last year might give last year's applicants' experience in this regard.