Computation of Development Ceiling
4.—(1)  For the purposes of determining the Development Ceiling of any land that is intended to be developed for any purpose, the following formulae shall, subject to these Rules, be applied:
(a)the value of the development described in section 36(7)(a) of the Act shall be determined in accordance with the formula (A1 x B1)
 
Where A1
is the floor area of the development for any purpose which was previously authorised under the Act or the repealed Planning Act (Cap. 232, 1990 Ed.) and is to be retained in the intended development; and
 
B1
is the rate corresponding to both the appropriate geographical sector of the land and the Use Group within which that purpose falls; and
(b)the value of the development described in section 36(7)(b) of the Act shall be determined in accordance with the formula (A2 x B2)
 
Where A2
is the floor area of the intended development for any purpose to be authorised by a written permission; and
 
B2
is the rate corresponding to both the appropriate geographical sector of the land and the Use Group within which that purpose falls.
(2)  Where any land or part thereof is intended to be developed for any purpose not falling within any Use Group, B2 in the formula in paragraph (1)(b) shall be such rate as the competent authority determines to be just and reasonable.