Actually, now that I test this, I'm losing with equal or greater valor.
Looking into MM_Full_unit_prod, they've got a charge bonus 4, melee 4, defence 1, armor 1, and honor 1.
FMAA have charge 3, melee 3, defence 2, armor 2, and honor 2.
Seems to be like it was described. I guess it's just because they've got more men...or something...