Something that just occurred to me:
Sending stored codes should issue consecutive codes from the list when multiple units are ordered. However, if your list of codes goes "A1,A2,A3,A4,Aetc...,B1,B2,B3,B4,Betc..." then there's a chance someone could order multiple tickets and get issued seat numbers at the end of one row and the beginning of the next, which would be across the room from each other. For this reason, you should specify the order of your "seating codes" in serpentine fashion, going up one row and down the next, e.g. "A1,A2,A3,A4,Aetc...,B20,B19,B18,B17,Betc..." so at least split-row assignments would be directly in front/behind each other.