SDCL § 58-24-50: Deviations to be uniform within class.

As to all forms of casualty insurance, including workers' compensation or any combination thereof, no application shall be granted under § 58-24-51 unless the requested deviation is based upon a uniform percentage decrease or increase to be applied to the premiums produced by such rating system, as filed, for a kind of insurance or for a class of insurance which is found by the director to be a proper rating unit for the application of such uniform percentage decrease or increase, or for a subdivision of a kind of insurance comprised of a group of manual classifications which are treated as a separate unit for rate-making purposes or for which separate expense provisions are included in the filings of the rating organization.