1. Determine the total amount of the several items of appropriation for the fund;

2. Deduct from such total appropriation the actual cash surplus of the immediately preceding fiscal year;

3. Deduct from the remainder thus ascertained the estimated probable income from sources other than ad valorem taxation; however, in no event shall the amount of such estimated income exceed ninety percent (90%) of the actual collections from such sources for the previous fiscal year. Also, deduct the estimated probable revenue to be derived from surplus collection from taxes in the process of collection of the immediately preceding taxable year; provided that the surplus so estimated shall be surplus cash as hereinafter defined, and shall include none of that portion of the reserve added at the beginning of such year for delinquent tax, and shall not exceed ninety percent (90%) of the actual collections of surplus back taxes legally accrued to and credited to the same fund account of the immediately preceding fiscal year;

4. Add to the remainder a reserve for delinquent taxes, the amount of which reserve shall be determined by the board, after taking into consideration the amount of uncollected taxes for the previous year or years; provided that the reserve so added shall not exceed twenty percent (20%) or be less than five percent (5%); and provided, further, that the reserve so added shall not be subject to review by the excise board;

5. Compute the levy necessary to raise an amount of money equal to the remainder thus ascertained, based upon the total assessed valuation of the district, taking into consideration any deduction which must be made because of the exemption of homesteads as required by Section 2406 et seq. of Title 68 of the Oklahoma Statutes; and

6. Compute the reduction in levy necessary to be made because of monies being required by law to be used for the purpose of reducing ad valorem tax levies.

The rates of levy for general fund, sinking fund and other purposes authorized by law shall be separately made and stated, and the revenue accruing therefrom respectively, when collected, shall be credited to the proper fund accounts.