Apologies if this has been asked before, I did search but couldn't find a relevant thread...

So, I was looking at the 2017 fleet list for Hertz and got to wondering about the hierarchy of the groups e.g. what counts as an upgrade, are any groups equivalent etc.

Is it as siimple as going down the list in order ?

A ECAR/EDAR Economy
B CCAR/CDAR Compact
C ICAR/IDAR Midsize
D SCAR/SDAR Standard
F FCAR/FDAR Fullsize
G PCAR/PDAR Premium
I LCAR/LDAR Luxury
Q4 IFAR Midsize SUV
L SFAR 5-Passenger SUV
L4 FRAR 7-Passenger SUV
T FFAR Large SUV
T6 PFAR Extra-capacity SUV
R MVAR/IVAR Minivan
S SPAR Large Pickup Truck
U STAR Convertible
N4 SKAR Cargo van
M FVAR Van