The key sentance is: “A battalion is capable of independent operations of limited duration and scope”
A general can send a battalion off on a mission like this to protect a number of Shieks in an area as large as al-Anbar.
So, it’s not just numbers; it’s the capability of the unit (if “unit” is the right word) to perform whatever the operation is? On another note, it’s good to hear more and more reports of local leaders like these sheiks cooperating with us rather than watching from the sidelines or engaged actively against us.