A complete record shall be made of all testimony taken and evidence received at such hearing, which record shall be filed in the office of the Board of Educational Lands and Funds. The examiner conducting such hearing shall make, in writing, complete findings and recommendations to the board as to the value of school lands according to classification. If the board determines that a change in the rental is justified it may either raise or lower its rental schedules according to classifications and schedules of valuations previously adopted based upon the evidence produced at such hearing as shown by the record, the effective date to be the time originally fixed.