10(1)The tribunal shall review the operation of the scheme within two months after the end of every year and shall give not less than twenty-one days' notice of the date, time and place of the sitting at which the review will take place, and at any such review the tribunal, after hearing any of the companies or any representative body of traders interested which may be desirous of being heard, and after considering all the circumstances (including the receipts of the companies in respect of the several selected traffics delivered during the year preceding the review for conveyance by railway), shall, subject as hereinafter provided, by order make in the scheme such modifications, if any, as they think necessary or desirable, but so that the provisions thereof shall comply with the requirements of this Schedule:
Provided that—
(a)the tribunal shall not by any such order alter the rate for the time being in force of any rebate provided for by the scheme unless—
(i)a debit balance is brought forward in the fund from the last preceding year; or
(ii)the tribunal is of opinion that in the year in which the review takes place the amount of the rate-relief of the companies will be less than the amount thereof estimated for the purpose of calculating the rebates in force, and that, unless such alterations are made, there will be a deficiency in the fund in respect of that year; or
(iii)the tribunal is of opinion that, unless such alterations are made, the aggregate of the rebates in respect of any group of selected traffics will, in the year in which the review takes place, fall short of a sum equal to the appropriate proportion of the net revenue of the fund for that year by more than the fixed marginal allowance; and
(b)the rates of rebates for the time being in force in respect of any group of selected traffics shall not be reduced by any alteration made under sub-paragraph (iii) of paragraph (a) of this proviso, unless the tribunal is of opinion that, if such reductions are not made, the aggregate of the rebates in respect of that group will, in the year in which the review takes place, exceed a sum equal to the appropriate proportion of the net revenue of the fund for that year by more than the fixed marginal allowance; and
(c)no alteration shall in any case be made in the rates of rebates to be allowed in respect of the selected traffics which would cause the aggregate of the rebates to be allowed in respect of any group of selected traffics to fall short of a sum equal to the appropriate proportion of the net revenue of the fund.
(2)In this paragraph the following expressions have the meanings hereby respectively assigned to them, that is to say:—
“Appropriate proportion of the net revenue of the fund ” means, as respects any group of selected traffics, the proportion specified in sub-paragraph (1) of paragraph 6 of this Part of this Schedule in relation to that group:
“Fixed marginal allowance ” shall in any year be taken to be, in relation to any group of selected traffics, an amount equivalent to one per cent. of the amount estimated by the tribunal as being the aggregate of the carriage charges made and to be made by the companies in respect of the traffics contained in that group, delivered in that year for conveyance by railway.