I had occasion to need a set of fingerprints for my job when I was living in G.I. 10 years ago. The NSP Troop C office had similar policies back then. When I called them they were pretty clear about their fingerprinting policy. At that time they told me they were using retired Troopers to do the fingerprinting. It sounds like their current policy may be similar to what it was 10 years ago.
I agree with RickDisney, call ahead, make an appointment, and KEEP the appointment. Back then, they were pretty cordial about the whole deal, but they didn't waste much time in getting my fingerprints done, or stand around to chat afterward. There were only a couple of other NSP employees in the office on the day of my appointment. I showed up on time, and was in and out pretty quickly. That situation may have changed some since CHP's came in however.