Is CO02 tcode authorisation necessary for Material Availability Check?

My Requirement: To insert a component in a production order and perform material availability check for that component via Custom program.

User does not have authorisation for tcode CO02.

After giving authorisation to following objects,

C_AFKO_ATY (ACTVT 02& AUTYP 10),

C_AFKO_AWA (ACTVT 02 , AUFART * , AUTYP 10 , WERKS * )

material insertion took place successfully.

But Material Availability Check did not take place until CO02 tcode authorisation is given.

Then how come Material Insertion in order took place without CO02 authorisation.

Thanks in advance.