Notwithstanding any other provisions of this chapter, the board may make an apportionment to any school district for the cost of leasing portable classrooms during the period in which additional school facilities are being constructed by a previously approved project, provided that each of the following conditions is satisfied:

1. (a) The district has received a final apportionment for the previously approved project and the construction of which has not yet been completed.

2. (b) Estimates of average daily attendance used for justifying the previously approved project indicate either of the following:

   1. (1) An increase over the base period of projection of at least 15 percent.
   2. (2) A substantial number of district classes being on triple session during the period of construction, as determined by the State Allocation Board.

3. (c) The district is making maximum use of its existing facilities through the operation of one or more continuous school programs.

   Any apportionment made to a school district pursuant to this section shall be added to the final apportionment for the previously approved project specified in subdivision (a), and the repayment thereof by the school district shall be made under the same terms and conditions as prescribed for the final apportionment.