Question about discharging:

So I haven't soldered my new plugs on these batteries yet, so I can't discharge using my car. I hooked them into my AC6 charger balanced them (perfect 4.2,4.2,4.2 &4.2) I was surprised both were perfect. I then discharged them a little bit. Down to like 15.8V and that took hours. Will this be ok to discharge to this volt aproximately? You guys said to charge and discharge a few times.