The following is with limited understanding and without any knowledge of terminologies in use in your establishment.
During Probation period employee is probationer and is not permanent. After successful completion of probation service shall be confirmed in writing.
The post on which you are appointed is permanent and no further sanction is required to make it permanent.
You shall officiate as………post granted to you. Generically officiating post might be a one step higher post.
Has the company described any officiating allowance in your appointment letter?
You may seek clarification from your personnel dept., appointing authority.
Valuable advice of learned experts/members is sought.
You may find the attachment useful.