To help diagnose why your shipping cost is multiplying per item (instead of staying flat), could you provide a bit more information on your setup?
- Please confirm your exact PrestaShop version (e.g., 8.2.x) and the PHP version running on your server.
- Carrier Configuration Screenshot: Can you share a screenshot of your carrier configuration, especially the “Shipping locations and costs” and “Costs by” sections?
- Cart Rule or Module Use: Are you using any shipping modules, overrides, or cart rules that might affect shipping (including third-party modules)?
- Product-specific Shipping Fees: Do any of your products have individual shipping fees set under the “Shipping” tab in the product edit page?
- Shipping Calculation Mode: In your carrier settings, is the “billing” set to “According to total price,” “total weight,” or “per item”?