I would agree. To make things even more cost effective i make my own weighted practice nocks. All you need is some

regular nocks (I use s-nocks)
5 min. epoxy
electric fence wire (or something simular gauge)
grain scale (about $45)

I find that the actual Nockturnal Nocks weight about 22 grains.

So I cut about an inch of wire mix up expoxy and use a toothpick to put epoxy into nock insert wire and stand nock on end for 24hrs to cure
Once cured weight what you made on the grain scale and start to nip off the wire until they are matched to the Nockturnals. Then you will have inexpensive practice nocks that if you happen to loose wont cost you a lighted nock.