How important are steps in computation of Income and tax liability questions

Income Tax will be a major question in section C.
That means you will need to show every working, every explanation and every thought process.
The clearer your workings and final computation are the better.

So the best thing to do is to have your computation take figures from your workings. Majority of your computation on the spread sheet should basically be linking to your workings so as to explain the computation easily and get you your unquestionable marks.

Basically they are not really worried about the figure (though it carries a mark) the majority of marks comes from the workings and if the examiner cannot relate your answer to the available workings then you will lose marks.

You need to answer in such a way that it is straightforward for the examiner to determine how you got Taxable Income or Net Income or Personal Allowance