A method and system for creating a levelling surface for use in levelling a substantially uneven ground surface, optimised for a single plane, row cropping, or dryland cropping with no rows. In one embodiment, the method includes receiving a content signal associated with regulated operations. When a mailer enters the identification code for the eligible postal facility where the mailer drops the mail for mailing, the drop ship file is used to determine whether the mail piece is available for DDU discounts based on the local ZIP code and the carrier route.