Excel seeing numbers not displayed in a cell

[asherwood]

I'm trying to use a formula to calculate how much the figure in cell D4 would be once increased by the percentage in N4 (so that if the answer was typed into D4, N4 would be 0%).

The correct answer - which you get if the sum in D6 is typed into a calculator - is displayed in D6 [£1,085.27] but as you can see I've had to type -1.82% into F6 (the cell which the formula in D6 refers to) to get that answer.

I want to be able do the same calculation using a formula to capture the -1.82% figure from cell N4, since this figure will change. But when I use the formula in cell D8, it comes up with the wrong answer [£1085.31]. It seems as though Excel is seeing numbers in N4 that aren't there which is why it's coming up with the wrong answer. Can anyone explain this?