A control system and method are provided for accumulating bales processed by an agricultural baler. The accumulator has a base frame and a carriage laterally movable thereon. The control system includes at least one actuator mounted to the frame and configured to move the carriage relative to the frame or to move the carriage in response to a bale engaging an upstanding end of the carriage, at least one sensor configured to detect a position of one or more of the carriage and the at least one actuator relative to the frame, and a controller configured to receive position signals and control the at least one actuator to move at least the carriage relative to the frame to sequentially accumulate multiple bales on the carriage. A crop package receiving area of the carriage has a fixed lateral width during all lateral movement of the carriage.