When a package is changed from an External Redirection, Parked, or Internally Redirected (IRM/IRO) domain to a different package, the existing package must be deleted before the new package can be setup. The same would be true where a full package downgrades to anything but a full package.
If the package is changing from a Starter, Basic, Silver, Gold, or Platinum account to a Starter, Basic, Silver, Gold, or Platinum account, the account does NOT need to be deleted and all files remain in tact. The main thing changed here is the amount of resources that are allocated to the existing account. Note however that where an account had MySQL access and it downgrades to a package without MySQL access, the MySQL access is removed.
The key is, no two accounts may share the same domain name or username at the same time on the server.
In your case we needed to remove the IRM account to free up the domain name for the full account on its own IP.
We do try to make it as quick as possible but it is something worth considering when you upgrade or downgrade to a package that will require the domain name to be "moved" to a different location on the servers. In these cases there is also a small amount of propagation since the IP address also changes.
I hope this helps to clarify
- Not all things are magical ...... yet