418Amount of allowances and charges
(1)The amount of the writing-down allowance to which a person is entitled for any chargeable period in respect of qualifying expenditure is—
(a)in the case of qualifying expenditure on the acquisition of a mineral asset, 10% of the amount by which UQE exceeds TDR;
(b)in the case of other qualifying expenditure, 25% of the amount by which UQE exceeds TDR.
(2)If the chargeable period is more or less than a year, the amount of the writing-down allowance is proportionately increased or reduced.
(3)If the mineral extraction trade has been carried on for part only of the chargeable period, the amount of the writing-down allowance is proportionately reduced.
(4)The amount of the balancing charge to which a person is liable for a chargeable period in respect of qualifying expenditure is—
(a)the amount by which TDR exceeds UQE, or
(b)if less, the allowances for earlier chargeable periods in respect of the expenditure less the total of any balancing charges for those periods in respect of the expenditure.
(5)The amount of the balancing allowance to which a person is entitled for a chargeable period in respect of qualifying expenditure is the amount by which UQE exceeds TDR.
(6)A person claiming a writing-down allowance or a balancing allowance may require the allowance to be reduced to a specified amount.