(A) For all injuries and disabilities occurring before January 1, 1987, the administrator of workers' compensation, for the purpose of carrying out sections 4123.412 to 4123.418 of the Revised Code and with the advice and consent of the bureau of workers' compensation board of directors, may levy an assessment against all employers at a rate not to exceed ten cents per one hundred dollars of payroll. If the administrator levies an assessment under this division, the rate of that assessment shall be determined annually for each employer group listed in divisions (A)(1) to (3) of this section. The rates determined under this division shall be sufficient to produce an amount no greater than the amount the administrator estimates to be necessary to carry out such sections for the period for which the assessment is levied. In the event the amount produced by the assessment is not sufficient to carry out such sections the additional amount necessary shall be provided, pursuant to section 4123.419 of the Revised Code, from the income produced as a result of investments made pursuant to section 4123.44 of the Revised Code. If levied, assessments shall be according to the following schedule:

1. (1) For private fund employers, except self-insuring employers:

   1. (a) For policy years commencing prior to July 1, 2015, in January and July of each year upon gross payrolls of the preceding six months;
   2. (b) For policy years commencing on or after July 1, 2015, in the month of June immediately preceding each policy year upon gross payrolls estimated for that policy year.

2. (2) For counties and taxing district employers therein, except county hospitals that are self-insuring employers:

   1. (a) For policy years commencing prior to January 1, 2016, in January of each year upon gross payrolls of the preceding twelve months;
   2. (b) For policy years commencing on or after January 1, 2016, in the month of December immediately preceding each policy year upon gross payrolls estimated for that policy year.
3. (3) For the state as an employer--in January, April, July, and October of each year upon gross payrolls of the preceding three months or at other intervals as the administrator establishes. After the completion of each policy year that commences on or after July 1, 2015, for private fund employers or that commences on or after January 1, 2016, for counties and taxing district employers therein, the assessments levied under this section shall be adjusted for the difference between estimated gross payrolls and actual gross payrolls reported by the employer on the payroll report submitted by a private employer pursuant to section 4123.26 of the Revised Code, or, for a public employer, submitted pursuant to section 4123.41 of the Revised Code. Amounts assessed in accordance with this section shall be collected from each employer as prescribed in rules the administrator adopts. The moneys derived from the assessment provided for in this section shall be credited to the disabled workers' relief fund created by section 4123.412 of the Revised Code. The administrator shall establish by rule classifications of employers within divisions (A)(1) to (3) of this section and shall determine rates for each class so as to fairly apportion the costs of carrying out sections 4123.412 to 4123.418 of the Revised Code.