Corporation Tax

Chinny Ltd
Chinny Ltd has prepared accounts for many years to 31 March annually, but recently changed its accounting date to 30 June by preparing accounts for the 15 months ended 30 June 2024. The company has a trading profit for this period, adjusted for all tax purposes except capital allowances, of £550,000.

The tax written down value of expenditure in the main pool on 1 April 2023 was £24,200 and on the special rate pool was £10,000. During the period ended 30 June 2024, the following transactions took place:

14 November 2023 Purchased a new machine at a cost of £14,800
3 February 2024 Sold equipment, for sale proceeds of £4,000, on which the 50% first year allowance had been claimed (the sale proceeds are less than the original cost).
11 June 2024 Purchased a second-hand van, cost £5,000.
The company had other income and gains in the period as follows:

Building society interest accrued: 1 April 2023 – 31 March 2024 1,420
1 April – 30 June 2024 780
Chargeable gains: Disposal 15 June 2024 30,768
UK dividends received: 18 October 2023 10,728
3 May 2024 14,868
Required:
(a)
Calculate the amounts of corporation tax payable for the 15 months ended 30 June 2024.

(a) Corporation tax computations
Year ended 3 months to
31 March 2024 30 June 2024

Study hubs Answer
Trading profits (W2) 422,364 103,994
Non-trade interest (building society) accrued 1,420 780
Chargeable gains – 30,768
Taxable total profits 423,784 135,542
Corporation tax at 25% 105,946 33,886
Lower limit = £50,000 × 3/12 = £12,500
Upper limit = £250,000 × 3/12 = £62,500

The only difficulty I encounter is pertaining to UK dividends received. In the study hub , they have not added the dividends to get augmented profits and have Directly calculated the corporation tax on taxable trading profits, could you please explain to me why did they do so?