Basics

”Top Tier™️” is a Fuel Performance Standard for Gasoline for use in Road Engines
It mainly assures a certain amount of Detergency (often via Fuel Detergent Additives ) thus cleaner Fuel Injectors and Intake Ports (If using Port Injection / Dual Injection etc)
Backed up via the standard+industry behind it, as well as via some studies (further digging needed on that)

Requirements

This info can largely be put on Fuel Specifications etc
The main question is how much additive needs to be added per gallon of Plastic Pyrolysis Oil Derived Gasoline

for making it up to Spec