With the free one car upgrade on Avis First, what is the break down on how that applies?

When I go to rent a car my selection order is the following:

Subcompact
Compact
Intermediate
Standard
Full Size
Specialty
Specialty
Premium
Intermediate SUV
Standard SUV
Luxury
Convertible
Standard SUV
Mini Van
Full Size SUV
Premium SUV
Passenger Van

If I select Standard I would get upgraded to Full Size, correct? But if I get a Full Size am I getting upgraded to a Specialty?

(all of this assuming the vehicles are available of course)

Thanks in advance!