No account shall be allowed by the board of county commissioners unless the same is made out in separate items, and the nature of each item stated, and where no specified fees are allowed by law the time actually and necessarily devoted to the performance of any service charged in such account shall be specified. Nothing in this section shall be construed to prevent any such board from disallowing any account, in whole or in part, when so rendered nor from requiring any other or further evidence of the truth and propriety thereof as it may think proper.
C.R.S. § 30-25-109