(1) If the commission approves a cost-tracking adjustment for electricity supply costs for a public utility regulated in accordance with chapter 8 or under this chapter, the cost-tracking adjustment must provide for:
(a) 90% customer and 10% shareholder sharing of costs, if cost sharing is required; and
(b) full recovery of costs incurred by a public utility as a result of qualifying small power production facility purchase requirements established in Title 69, chapter 3, part 6.
(2) A cost-tracking adjustment may not include a deadband.
(3) For the purposes of this section, "deadband" means a level of cost recovery variance, including levels of underrecoveries and overrecoveries to be borne by the public utility.