Role of Line Manager v. Staff Specialist

Recently, my professor, Dr. Jeffrey of CMU, sent this link to clarify the roles of line and staff managers. 

https://blackboard.cmich.edu/webapps/portal/frameset.jsp?tab_tab_group_id=_2_1&url=%2Fwebapps%2Fblackboard%2Fexecute%2Flauncher%3Ftype%3DCourse%26id%3D_42205_1%26url%3D

The distinction is clear.  When applied to an educational context, line managers manage specific sub-divisions of a school (or the whole thing) and are after results.  This is more of the traditional top-down model.  Line managers have authority and power.  Staff managers are management… but they are facilitators and assist line management. 

The line manager of my school is the principal and the staff managers are specialists such as the two assistant principals (assigned to discipline and curriculum respectively), dean of discipline, and operations/office manager.  

Sometimes I would much rather be a staff manager/specialist than line management.  Today's small school / charter environment sometimes necessitates that a building principal move beyond traditional line management and that he simultaneously delve into the realm of the staff manager.