The director may, from time to time, and as often as occasion may require, but not to exceed two meetings in any one calendar year call into conference the probation officers of the several counties, or such of them as he may deem advisable, for the purpose of discussing the duties of their offices.

The actual and necessary expenses of the probation officer incurred while traveling to and from and while attending the conferences shall be a county charge; provided, prior approval of the board of supervisors has been obtained.