It's three weeks until late fees kick in (after Sept 2), with registration closed after Sept 16, so enter now, especially if you have vacation plans at the end of August to distract you.
Anyone registering for the M/F-21+ *or* M/F-20 classes must have a IOF world ranking number for which you can sign up easily at Eventor.
Information and links are on the
NAOC 2016 website particularly the Registration and Fees page.