The account of such county clerk shall be presented to the board of county commissioners of the new county, said account to be itemized and verified, showing his expenses and services for such work, which shall consist of money, if any, actually expended by him for books of record in which the transcripts had been entered and a charge at the rate of fifteen cents [($.15)] per one hundred words for copying, comparing, indexing and certifying the transcripts of records and he shall be allowed interest on all deferred payments at six percent per annum.