Unable to create items when generated based on EFF attribute values

Summary:

Unable to create items when generated based on EFF attribute values & incremented by existing item number . Requirement is to fetch the latest item number from System based on Product family attributes created and create new item with increment in sequence. Ex:  1.MS - 00100 - Above Product family attribute has MS001001001 item created in system, when they are creating items with same product family attributes, new items with MS001001002, MS001001003 items should be created. 2. MS- 00200 -  Above Product family attribute has MS002001159 item created in system, when they are creating items with same product family attributes,