Custom Fields in Professional and Enterprise Editions

I'm still in my trial period so I've been switching between the Professional and Enterprise versions to see which one best fits my company's needs. In one of my modules, I exceeded the limit for custom fields in the professional version while I was working with Enterprise, but when I switched back, they all stayed in their places. Does this mean that if I were to go with the Professional CRM, anything custom functions that I enabled while I was using Enterprise will stay even if they are incompatible with Professional?

Thank you!