Lol. They aim for the armored helmet instead of the completely unprotected face which is a larger target.
You do aim for the helmet when you're targetting a formation....
Lots of shots fall slightly short and will get the face, and if it hits the helm and, instead of penetrating, ricochets, the bolt is very likely to hit someone else in an inconvenient place further back where they don't expect to be hit....
And if the unit you're targetting is moving at a brisk pace, the original target will not be there, but the
second row will be hit.
Combat archery is very much not scoring points on a target pack... And has its own little tricks of the trade..