³ It shall be lawful for the State Government—
(1) to levy on all private estates under Government management a rate not exceeding five per cent. on the gross income, calculated as nearly as may be possible, to cover—
(a) the cost of all Government establishments in so far as they may be employed in the supervision or management of such estates other than establishment specially entertained for the supervision or management of any particular estate or group of estates, and
(b) all contingent expenditure incurred in consequence of such supervision or management;
(2) from time to time to vary such rate; and
(3) to reduce or remit such rate in any special case or case as may be equitable:
Provided that, in deciding the amount of the rate to be levied under this Act on any particular estate or group of estates, the State Government shall consider the expenditure incurred on special establishments for such estate or estates.