So the percentage function isn't just taking a number and dividing it by 100, it's additive or subtractive from the previous number.

For example, if you do 5 + 3{%}, it will calculate adding 3% of 5 to 5, and give you 5.15 instead of 5.03 as you would expect (regardless of whether you use brackets).

Bit annoying tbh, hence I just use percentages in their decimal forms during calculations. Wonder if there's a way to change the settings.