Comment 1 for bug 89515

If the account is set up as the default account, that is, it is the one selected on the User Setup page, it should add the user to the admin group. However, if it is not selected as the default account then it will not be added to the admin group.

This is by design and is mentioned in the specification (https://wiki.ubuntu.com/MigrationAssistance):
"We do not present the option to make one of the users an administrator as that is already covered in the UserSetup dialog for the first user."

I'm marking this as rejected. If you did make the admin account from Edgy the default user by selecting it at the User Setup page, feel free to reopen it.