Florent Mirieu worked on stabilizing delivery calculation reliability in the eCommerce checkout flow for the brain-tec/odoo repository. He addressed a singleton error that occurred when multiple delivery lines were present in the cart, updating the backend logic in Python within the Odoo framework. By isolating the bug and introducing a targeted fix to the cart controller, Florent ensured accurate delivery totals and reduced the risk of incorrect charges. His approach focused on minimizing regression risk and aligning technical improvements with business needs, ultimately enhancing checkout reliability, customer trust, and support efficiency through well-documented, maintainable backend development practices.