(a) The local government may levy a sales or use tax pursuant to any other currently existing statutory authority to levy the tax and provide that the proceeds generated by the tax are to be used for any purpose authorized by this subchapter.
(b) The Department of Finance and Administration will administer and collect any sales or use tax levied under this section if the Department of Finance and Administration would have administered and collected the tax had the tax been levied solely pursuant to the primary statutory authority to levy the tax. The primary statutory authority to levy the tax is the statute upon which the local government relied for levying the tax, not this subchapter.