And whereas by divers Acts certain limited Penalties or Terms of Imprisonment are imposed for Offences therein mentioned, and sufficient Power is not given to the Justice or Justices before whom the Offender is convicted to reduce or lessen such Penalty or Term of Imprisonment, whereby much Hardship is experienced; be it enacted, That where by any Act now in force or hereafter to be passed a limited Penalty or Term of Imprisonment is imposed on Conviction of an Offender before a Justice or Justices of the Peace, it shall be lawful for any One of the said Magistrates before whom such Conviction shall be had to reduce or lessen such Penalty or Term of Imprisonment in such Manner as he may think fit: Provided always, that no Penalty for the Infringement of any Act relating to the Revenue of Customs or Excise, Stamps or Taxes, shall be reduced by any such Magistrate below the Amount or Proportion allowed in that Behalf by the Act, or Acts specially relating thereunto without the Consent of the Commissioners of Customs or Excise or Stamps and Taxes respectively.