Current candle is greater/lesser than previous candle close in successive periods = add to the length
In the case of reversals, price tends to spike up, retrace, then reverse. In that event, the resets length to catch up before a full reversal occurs.
When price moves uniformly in one direction, the length increases excessively to prevent chop.
Similar to a Dynamic, except weight isn't give to a particular direction.
Sorry if I haven't replied to your message yet, I'm a bit backlogged :)