xmlns:atom="http://www.w3.org/2005/Atom"
13The amount by which the estimated aggregate of the debits referred to in head (b) of paragraph 12(1) of this Schedule exceeds the estimated aggregate of the credits referred to in head (a) of the said paragraph 12(1) shall be expressed as a fraction of the estimated aggregate of the total housing valuations referred to in head (c) of the said paragraph 12(1).