It makes sense to complete enough of the application to qualify for DODMERB (medical) consideration as early as you can. Typically, that is when 60% or so of the USNA application is completed, and your student is considered to be competitive. Two key ingredients of this consideration are SAT/ACT results and transcripts so I would submit these when you can. If the SAT is low, as you noted, then you will want to submit the August scores. Additional scores should be updated for October, November and December, which are the 'next' dates for the SAT. I advise all of my students to continue to update the admissions counselors all the way through January 31 -- that means scores, awards, new positions, promotions and any other 'news' that impact his whole person score.