(a) Subject to the limitations included in subdivision (b) of this section, the operation authorized by a permit to a bus company, pursuant to section 154, subdivision 3 of the Transportation Law, shall be the transportation of special or chartered parties originating at any route point, as defined in section 700.1(h) of this Part, and from that regular route point to any point in the State. It may also include return transportation to the point of origin, but only when such return trip completes a round trip for the same persons boarding at the authorized regular route point at which the trip originated.

(b) The transportation of special or chartered parties from any regular route point shall be subject to the restrictions or limitations imposed by the underlying certificate of public convenience and necessity.