At any time after the commissioners have assessed the cost of the project upon the benefited land within the district and the costs of the portion of the project used for the generation of electric energy, the board may direct the commissioners to reassess the costs of the project upon the benefited land. At the expiration of five years after the commissioners have originally assessed the cost of the project upon the benefited land within the district and the costs of the portion of the project used for the generation of electric energy, and thereafter at any
time not less than five years after the next previous reassessment, the board, upon petition of holders of title to 10 percent of the land, shall direct the commissioners to reassess the costs of the project upon the benefited land.