The unknown flags in shishi are actually for the sprite's "height" value - most units are 36 (3 tiles), Altima 1 is 60 (5 tiles) and Altima 2 is 120 (10 tiles) tall. This affects things like arrow arcing and deciding where a unit can pass on the map if there's a spot where there's a higher tile on the same X/Y (like in the cases of bridges).