Suggestion:
No, System does not maintain multiple expiry dates for single item & lot. Stock is inwarded from Purchase Receipt, Adjustment Receipt and Sales Return. System allows to add the stock and enter the lot numbers through these transactions and the details such as lot number, rate, mfg date, expiry date, etc are saved in item lot info table which is maintained centrally. In itemchange the system sets the lot number from item lot info and whenever the item of the same lot number is inwarded these details remains the same.