(1) For the purposes of this section -
(a) interest shall be treated, if not otherwise so treated, as accruing from day to day, and
(b) references to "general crediting date", as respects a relevant deposit taker, shall be construed as references to a date on which the relevant deposit taker credits to all, or to the majority, of relevant deposits held by it on that date interest accrued due on those deposits (whether or not the interest is added to the balances on the relevant deposits on that date for the purpose of calculating interest due at some future date).
(2) Where for any year of assessment the amount of appropriate tax due and payable by a relevant deposit taker for that year under section 258 is less than the amount of appropriate tax which would have been so due and payable by the relevant deposit taker for that year if the total amount of the interest which had accrued, in the period of 12 months ending on -
(a) the general crediting date as respects that relevant deposit
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