It is also common for the crane's to be lowered or removed when weather conditions require it - i.e. the ILS is being used to minima. Perhaps the NOTAM means that when the weather is reasonable, the crane's are up, so you only need know about it if you are conducting the non-precision approach (for practice or training), if the weather actually requires an ILS approach, the crane's are lowered/removed so the ILS minima is not affected?