I just got off the phone with the MOA, and the way they explained it is.
If you preregister for the national between March 1 and March 31 the cost for members is $40.00.
After March 31
MOA Members – $50 pre-registration, $60 gate registration.
Non-Members – $70 pre-registration, $80 gate registration.
Below is the link to pre preregister