I think you missed the very clear part of PayPal's policy:
(bolding added by me to show you the requirement you missed)1.5 What is "Proof of Delivery"?
Online documentation from a shipping company that includes all of the following:
- The date the item is delivered.
- The recipient’s address, showing at least the city/state or zip code (or international equivalent).
- Signature Confirmation for payments of $250 USD or more (see Foreign Currency Equivalents below).
Based on PayPal's written policy and the above outputs of your two tracking numbers (Priority vs. Express), I think it's crystal clear that Express is required for Seller Protection. If I was a yankee seller, I'd always be sending Express.