Hi,
Self Life Expiration Date !
I think you can better to do the validation in EXIT_SAPLV01Z_004! ( Check New Batch Number According to Customer Rule)
You can extended the structure with the field for validation! Please read the below documentation
Using this customer function call (CFC), you can use your own rules to check if a manually entered batch corresponds to certain numbering conventions.
The communication structure X_BNCOM contains the application data known up to this time. You can extend this structure in the DDIC using the structure BNCOMZ.
If you set the parameter CUST_NOT_ALLOWED, you reject the batch number. This leads to an error in the calling application and therefore to rejection of the batch number