The state board of registration for professional engineers and surveyors, subject to the approval of the controlling board and except for fees required to be established by the board at amounts "adequate" to cover designated expenses, may establish fees in excess of the amounts provided by sections 4733.01 to 4733.99 of the Revised Code, provided that such fees do not exceed the amounts permitted by these sections by more than fifty per cent.
R.C. §4733.25