For what it's worth, the "new" AWD for Costco US that you can use to book directly via avis' website is

A108353

site note: ABG meta search tool that doesn't enforce the annoying corporate 2FA and IDs for AARP etc shows you everything about your reservation, the URL is

https://book1.carrental.com/dcweb/sl...=CSL&locale=en

I found this via Avis Thailand's website 5 or 6 years ago, and it's the go-to for making any reservation