Successive provisional appointments of 90 working days or less each may be made in any class in the absence of an appropriate eligibility list; provided, that continuous examination procedures for the class have been authorized by the commission. Such successive provisional appointments may be made and persons employed in temporary capacities under a given governing board for a total of more than six months in any one year. Such appointments may continue for the length of time for which they were made, but may not be extended if a certification can be made from an appropriate eligibility list. While this section is in effect, it shall supersede any other provisions of this article which are in conflict with this section, but only to the extent there is a conflict.