I believe:
A = Economy ----> YA Specialty Economy
B = Compact-----> YB Specialty Compact
C = Midsize------> YC Specialty Midsize
D = Standard----> YD Specialty Standard
E = I think it a Fusion and some others
F = Fullsize------> YF Speciality Fullsize
G = Premium
H = Premium Elite
Q = Midsize SUV
T = Super SUV
and so on....
All the Y is XM, sunroof, leather, or something extra like that...