Why are Theurophoroi so weak?

[Tellos Athenaios]

Two of the extra armour points are for the thureophoroi's greaves (the Epeirote thureophoroi skin lacks these because it was originally used for a different unit), but I am not sure where the third point comes from.

Which third point. 11+9+3+1 = 9+11+3+1 (as per screenshots).
Pseudo-random factoid: as far as helmets go cheek pieces etc. are awarded some extra armour points too...