I seem to remember the PLRF-05 doesn't have a true NV mode. There are a few posts elsewhere around here that mention responses from Potomac stating this to be the case even though the manual states otherwise. Worth looking into.
Tthe PLRF-05 has not got any NV setting , the PLRF-10 does but obviously it is a more expensive device & complete device , also the Ashbury mount was manufactured for the 10 model though ,