Terminal loss relief – Michael & Sean problem

Hi Sir,

on the problem Michael & Sean (06/12) amended we have the following.

Sean ceased trading on 31/12/2017. He prepared the accounts anualy on 31/12
The profits for the last 5 years were:

31/12/2013 – 21 300
31/12/2014 – 14 400
31/12/2015 – 18 900
31/12/2016 – 3700
31/12/2017 – (23 100)

Unused overlap profits brought forward are 3 600.

My question is why we add the overlap profits to the loss from 31/12/2017 as a loss.
The solving says that we add the overlap profits to the loss of the year ended 31/12/2017, so the total loss will be 23 100 + 3 600 = 26 700
And only after, we set off against the profits from previous years

Thank you