Section 203. Expenses incurred in the performance of official duty

1.  The
  actual and necessary expenses of all officers and employees, other  than
  supervisors, paid from county funds incurred in the performance of their
  official   duties,   and  the  actual  and  necessary  expenses  of  all
  supervisors incurred in the performance of  powers  and  duties  of  the
  county, shall be a county charge.
    2.  The board of supervisors may authorize the payment of a reasonable
  mileage allowance for:
    (a) the miles actually and necessarily traveled on  official  business
  by  any such officer or employee, other than a supervisor, by the use of
  his own automobile; and
    (b) the miles actually and necessarily traveled on  official  business
  of  the  county  by  any  supervisor  by  the use of his own automobile,
  including travel on official business of the county in  going  from  and
  returning to his residence.
    3.  Whenever  the board of supervisors is directed or empowered by law
  to appoint a commission or board, by whatever title known, to  render  a
  service  for  the  county, such board of supervisors may provide for the
  audit and payment of actual  and  necessary  expenses  incurred  in  the
  performance of duties including the mileage allowance.
    4.  No  supervisor,  officer  or employee shall be allowed or paid any
  lump sum in lieu of actual and necessary disbursements incurred by him.