The governing board of a school district maintaining an alternative school may provide in whole or in part for the transportation of a pupil attending the alternative school. In lieu of providing such transportation, the governing board may pay to the parents or guardian of the pupil a sum not to exceed the cost of actual and necessary travel incurred in transporting such pupils in cases where transportation is provided by or paid for by the parents or guardian; provided, that in no case shall the district’s state apportionment for transportation expenses be increased because of the operation of an alternative school.