376Calculation of allowance after acquisition
(1)This section applies if—
(a)section 375 applies, and
(b)the acquisition is a balancing event under section 381 (as a result of an election made in accordance with section 382).
(2)The writing-down allowance for a chargeable period ending after the event is—
RQE is the residue of qualifying expenditure immediately after the event,
A is the length of the chargeable period, and
B is the length of the period from the date of the event to the end of the writing-down period.
(3)On any later acquisition that is a balancing event under section 381, the writing-down allowance is further adjusted in accordance with this section.
(4)The residue of qualifying expenditure immediately after a balancing event is calculated as mentioned in section 386, taking into account any balancing adjustment falling to be made on the event.
(5)For this purpose, any balancing allowance on that or any previous balancing event which is reduced or denied under section 389 (sale subject to subordinate interest) is to be treated as having been made in full.
(6)The allowance is proportionately reduced if the person entitled to the allowance is not entitled to the relevant interest in relation to the expenditure in question during part of the chargeable period.