(a)if it considers it necessary or expedient so to do for the proper and efficient management of the work of assessment and collection of revenue, issue, from time to time (whether by way of relaxation of any of the provisions of sections 263, 270, 271, 279, 280, 287, 288, 298, 398(3), 406, 407, 408, 423, 424, 425, 427, 428, 439, 448, 449 or otherwise), general or special orders in respect of any class of incomes or class of cases,––(i)setting forth directions or instructions (not being prejudicial to assessees) as to the guidelines, principles or procedures to be followed by other income-tax authorities in the work relating to assessment or collection of revenue or the initiation of proceedings for the imposition of penalties; and(ii)any such order may, if the Board is of the opinion that it is necessary in the public interest so to do, be published and circulated in the prescribed manner for general information;