I'm experiencing an ongoing issue with maintaining our One-Time Delivery Rate, currently at 90.91% without promise extensions. After reviewing our delivery report, I found ten orders that were shipped on time via Ground Economy and arrived on their expected delivery dates. However, a specific timing factor tied to the promised delivery dates seems to be impacting our rate, as USPS hasn’t consistently met the required delivery time on these dates. Given USPS’s timing variations, I believe the timing element shouldn’t be a determining factor here.

We have Shipping Setting Automation (SSA) enabled, which seems to calculate delivery days accurately, so the issue appears isolated to the timing requirement on the delivery date. While I’ve read that using the "Buy Shipping" option (purchasing postage directly from Amazon) could mitigate these negative impacts, our direct NSA contract with USPS is significantly more cost-effective.

Side note: It’s frustrating to face penalties for using the same service independently of Amazon’s platform.

Please help!!!