Referring to this last application cycle, the PTCAS website says: "The Early Decision application deadline is August 15, 2012. In addition to completing the PTCAS application,
you must arrange for PTCAS to receive all of your official U.S. transcripts and fee by August 15."
http://www.ptcas.org/ptcas/public/earlydecision.aspx?navID=10737426886
It seems like it would be difficult to get your updated transcript to PTCAS by Aug 15 if your last day of school is Aug 8. You would have to wait for grades to come out (my schools usually took 1-2 weeks for that), then arrange for the transcript to be sent along with the PTCAS form and received by PTCAS 7 days after your last day of school. PTCAS can also take a day or two (or sometimes more) after actually getting the transcript in the mail before it is officially "received" in their system.
The Aug 15 deadline refers to when you need to e-submit and have all your transcripts in to PTCAS, not when your school needs the materials. So if you are somehow able to get your transcript to be received by PTCAS by Aug 15, you should be able to meet the deadline. However, getting that transcript in on time seems like the challenge. Also, yes, you can e-submit your application before all your transcripts are in, but PTCAS won't start processing your application until they have all your transcripts.
By the way, if you submit in August, it won't take 5 weeks for PTCAS to process your application. I submitted in late August last year, and it took only 2 days for PTCAS to process it (after they already had all of my transcripts). It starts taking a month or more to process when they get really busy, starting around late September and October.