Switch between individual and professional plans

I just downgraded my newly registered seller account from professional to individual in North America (US, Canada, Mexico). It looks like it defaults to be professional even if you select ‘individual’ during registration. After I went to ‘account info-manage your service’ and downgraded to individual, the US and Canada quickly became ‘individual’ but the Mexico store is still remaining ‘professional’. I don’t know what’s happened. And, according to Amazon’s official guide, I can switch between individual and professional at any time, right?