[I]t has long been the rule in Pennsylvania that the word "shall," although usually mandatory or imperative when used in a statute, may nonetheless be directory or permissive, depending upon the Legislature's intent; we ascertain this intent after reviewing the entire act, its nature, object and purpose, the respective consequences of various constructions of the particular statute, and after determining whether the action allegedly mandated by the statute is the essence of the thing to be done pursuant to it. Tyler v. King, 344 Pa. Super. 78, 496 A.2d 16 (1985)
10 Pa. Code § 13.51