(a) Each school district shall maintain records for each school bus that will clearly show the number of normal pupils transported between home and school who board the bus at a regularly scheduled stop:
(1) With the minimum transportation distances specified in Section 15241.
(2) Beyond such minimum transportation distances.
(b) The number of pupils so boarding the bus is ascertained by one of the following methods:
(1) The average of an actual daily count.
(2) The average of an actual count on four normal school days occurring on or about October 1, December 1, February 1, and May 1.