Chapter 18: Terminal loss relief in corporation tax

Hi sir,

In chapter 18 , example 4 , why do we calculate maximum loss to set off for the year ended 30th Sep 2017 but we don’t calculate the maximum loss to be set off for the period of 6 months to 31st March 2018 ?

Also why don’t we time apportion the total profits for the period of 6 months to 31st March 2018 when it’s not an accounting year end ?