The Board may: hear and decide appeals when: it is alleged that there was an error in any order, requirement, decision, or determination made by an administrative official or unit under this title or any local law adopted under this title; and the Board is authorized by the Mayor and City Council of Baltimore City by local law or the Charter of Baltimore City; hear and decide special exceptions or conditional uses on which the Board is required to act under a local law; authorize on appeal in specific cases a variance from the terms of a local law; approve buildings and uses limited as to location by any regulation adopted under a local law; and when acting on a zoning application, consider the availability of public facilities in the area, including schools and flood plain facilities, under regulations adopted under a local law. If authorized by the general zoning laws of Baltimore City, this subtitle does not prevent the Mayor and City Council of Baltimore City from granting by local law: variances; special exceptions; or conditional uses. Nothing in this subtitle prohibits an administrative official or unit from making a decision under this title or any local law adopted under this title when authorized by the Mayor and City Council of Baltimore City by local law or the Charter of Baltimore City. This section does not alter or impair the right to appeal provided for under this subtitle.