ACCA Mock – Pre Sept 23 MCQ 2

Kasper is employed by CK Ltd. On 6 April 2021 he was provided with a computer worth £3,200 for private use. On 1 January 2023 CK Ltd gave Kasper the computer when it had a market value of £1,500.

-£2080
-£2560
-£3200
-£1500

So I thought it was the higher of MV when gifted vs MV when first available less BIK during time of use.

so higher of £1500 or £3200-(£3200*0.2)-(£3200-0.2/12*9)=£2080. Therefore I had put £2080 as my answer.

However on ACCA, the answer is £2560. Why do you only deduct the 21-22 benefit???
this is the answer on ACCA.

‘£2,560
2022-23:
Use of computer until 31 December 2022: 20% x £3,200 = £640 x 9/12 = £480
Gift of computer on 1 January 2023:
Higher of:
Market value at date of gift £1,500
Market value used for benefits calculation less amount assessed: £3,200 – £640 (2021-22) – £480 (2022-23) = £2,080 ‘

It does all the same calculations but then gives a different answer at the top?