(a) A person who is convicted of a misdemeanor of a high and aggravated nature shall be punished by a fine not to exceed $5,000.00 or by confinement in the county or other jail, county correctional institution, or such other places as counties may provide for mainte-
nance of county inmates, for a term not to exceed 12 months, or both; provided, however, that a person convicted of a misdemeanor of a high and aggravated nature which was committed by an inmate within the confines of a state correctional institution and sentenced to confinement as a result of such offense shall be sentenced to confinement under the jurisdiction of the Board of Corrections in a state correctional institution or such other institution as the Department of Corrections may direct for a term which shall not exceed 12 months. In all cases of a conviction of a misdemeanor of a high and aggravated nature, the sentencing court shall retain jurisdiction to amend, modify, alter, suspend, or probate sentences imposed under this Code section at any time; but in no instance shall a sentence imposed under this Code section be modified in such a manner as to increase the amount of fine
or the term of confinement.
(b) Notwithstanding any laws to the contrary, a person sentenced for a misdemeanor of a high and aggravated nature may earn no more than four days per month earned time allowance.