Assuming a current CCO contract, you can UPDATE your existing code.
Changing to a higher feature set is an UPGRADE, which is not allowed.
An IP Base IOS might only cost US$100.00, the Enterprise Security Suite is several thousand.
You can Update (i.e., IP Base 12.0 to IP Base 12.3) but you cannot / should not Upgrade (i.e. Ip Base 12.0 to ADVSECURITY 12.3).
Good Luck
Scott