Section 2903. Enumeration of Powers of Departments, Boards, and Commissions.--Whenever in this act the powers and duties of a department, board, commission, or officer are enumerated and defined, such enumeration and definition shall not be construed to be in derogation or limitation of the powers and duties heretofore exercised and performed by such department, board, commission, or officer unless:
(a) Any power or duty, as enumerated and defined, is clearly inconsistent with the exercise of a power or the performance of a duty heretofore exercised or performed;
(b) There is a specific statement that a power or a duty heretofore exercised or performed shall not be exercised or performed by such department, board, commission, or officer, or that such power or duty shall be exercised in a different manner.