(b) The legislative body may establish a procedure, subject to the approval of ORPTS, for making these adjustments. Where no locally applicable procedure has been established or approved when the adjusted base proportions are determined, the legislative body shall adjust the current base proportions in the following manner:

1. (1) A change in level of assessment factor shall be computed for each class and each portion class as follows:

   1. (i) Determine the physical or quantity decrease for the class or portion class by summing the decreases due to physical or quantity changes in the class or portion class, excluding special franchise properties in the nonhomestead class, from the reference roll to the levy roll.
   2. (ii) Determine the surviving total assessed value of the class or portion class by subtracting the physical or quantity decrease so determined from the total assessed value of the class or portion class, excluding special franchise properties in the nonhomestead class, on the reference roll.
   3. (iii) Determine the net equalization change of the class or portion class by separately summing the increases and decreases for equalization, excluding special franchise properties in the nonhomestead class, and subtracting the sum of the decreases from the sum of the increases.
   4. (iv) Determine the change in level of assessment factor by dividing the net equalization change by the surviving total assessed value of the class or portion class, expressing the quotient to at least four places to the right of the decimal point, and adding one to the quotient so determined.

2. (2) The taxable assessed value of the property on the levy roll, at the reference roll level of assessment, shall be computed for each class and portion class as follows:

   1. (i) Divide the taxable assessed value of the property in the class or portion class on the levy roll, excluding special franchise properties in the nonhomestead class, by the appropriate change in level of assessment factor.
   2. (ii) For the nonhomestead class, add to the quotient so determined the taxable assessed value of any special franchise properties in the class or portion class on the levy roll, at the reference roll level of assessment. Such taxable assessed value shall be computed by ORPTS and provided to the legislative body of the homestead assessing unit no later than five days before the last date provided by law for the filing of the levy roll or 30 days prior to the last date provided by law for the levy of taxes, whichever is sooner. The provisions of Part 8197 of this Title shall apply to the extent practicable to the computation of such taxable assessed value; provided, however, that the inventory to be valued shall be the inventory applicable to the levy roll, but the valuation standard and State equalization rate to be applied shall be the same as if the property were being assessed for the reference roll.
3. (3) An adjustment factor for class quantity changes shall be computed for each class and portion class by dividing (i) the taxable assessed value of the class or portion class on the levy roll, at the reference roll level of assessment (i.e., the taxable assessed value determined pursuant to the preceding paragraph), by (ii) the taxable assessed value of the class or portion class on the reference roll, including special franchise properties in the nonhomestead class.

4. (4) The adjusted base proportions for the homestead assessing unit and each portion thereof shall be determined as follows:

   1. (i) Multiply the current base proportion of each class or portion class by the appropriate adjustment factor.
   2. (ii) Sum the products so determined. If the sum is not 1.0000 for the homestead assessing unit or portion thereof, divide each class product by such sum.