Seems low, but if its not going out on your, great! I think the setup numbers for most LL are min 6 and max 40.
When burning max (raise your room temp up 5-8 degrees) and let it run for an hour or so until you reach FR99 (feed rate), do you have about 1" of ash? if not, then you can increase the max a few points at a time and keep checking it. if pushing coals off the end, back it down.
It's kinda of experiment, each stove (and coal) is slightly different, so you just have to play a bit to get max output without wasting.