There is simply no way RNP relates to ILS. Unless one forces the issue and tries to apply RNP calculations to LOC accuracy, a bit like calling MNPS RNP 12.6. If track spacing works out to a bit under 60 nm, then 95% of the time the plane must be within 12.6 nm of actual position because it must be within 60nm 99% of the time.
GF