Grand Arena Championships – GP Divisions [MEGA]

so... a question

i run an alt character, and he's a little over 600k GP, in Division 10. Somehow, i got paired w/ a bunch of opponents in Division 9, with 300k more GP than me, there's even 1 Div 8 opponent. Isn't the very essence of having Divisions that you're paired with people IN your Division? what gives?