I think the signs on the adjustments may be the wrong way round?
Rolls are subtracted, not added, I do see how the wording is confusing and will update soon, thank you for the heads up! The section on Combat is clear about it but the section on Ability Tests is not.
Important Thing to Remember:
Subtracting a negative number results in Addition (which is bad for your roll).
Just remember that 3 - -2 = 5