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?