Often in sections A & B there are questions in which you have to input the number yourself. I prefer to calculate discount factors myself rather than look them up on the provided tables, because it’s far quicker for me to do so.
Would the acceptable answers always have a range which included those calculated discount factors which may differ slightly from those calculated via the tables? Technically those answers are actually more accurate anyway.
The figures that relate to discount rates in ‘real’ exam questions , live mocks etc will always be accepted within a range of answers.
This is due to exactly what you have said some candidates use tables, some use formulas either themselves or by using calculators. All with give a slightly different answer.