All persons who have performed services required under this chapter, which services are made compensable under the terms of this chapter, shall, in case of injury or death arising out of and in the performance of the functions pursuant to this chapter, or their dependents, be entitled to all of the benefits provided in chapter 386 including medical services and supplies; provided that for the purposes of such benefits, average weekly wages shall be computed on the basis of earnings from the usual employment of such persons. The cost thereof shall be a charge upon the appropriate fund.