That does not really make a lot of sense, N is always in the range or N+/-0.5%, right?
Lets assume you want to compare if one number (X) is within 0.5% of another number (N), you could multiply N with 1.005 for the upper limit and 0.995 for the lower limit, then use "in range and coerce" to see if X is in range.
If that's not it, please clarify your question with more details.