The sending of messages in copy and hidden copy through the SMTP server will be managed independently. This means that a credit will be used for each message sent, be it the main one or the copies. All messages you send will be classified the same.
For example, if you send an email with a copy of CC and another in BCC, you will use three of the credits in your account. For the purposes of the credits of your account, both the main message and the copies will be considered in the same way.