Tables MCHA and MCH1

Hi ,

When I am creating a batch from tx MSC1N , if I do not assign a plant while creating the batch it gets saved to the table MCH1 and If I create a batch with the plant information then it gets saved to the table MCHA.

That is , batches for a material get saved to the MCH1 table as well as the MCHA table (if a plant is assigned) while the ones that are not assigned to a plant get saved to the MCH1 table only.

Could you kindly let me know the difference between the tables MCHA and MCH1 and why this happens ?

Thanks.