Cumulative volume waves can be displayed in 2 distinct modes: signed and absolute.

Absolute waves are much the same as traditional waves: volume of every bar is accounted in the running total according to wave direction (upward wave = plus, downward wave = minus) - no matter of the bar direction itself. This simplified classical approach was intended to help with sorting out bar volumes, which are usually presented as a single integral value per bar (buys and sells combined together).

But since this indicator is created not only for plain old volume waves, but primarily for volume delta waves, it provides 2 separate components of volumes per bar and their effective delta (with positive or negative sign). Hence it makes sense to respect the signs during volume accumulation. This is done by the signed mode. When it's enabled the running total may not only increase, but also decrease in the wave, if specific volume delta sign is opposite to the wave sign. Such anomalies are hidden when traditional (absolute) volume waves are used, but they (anomalies) are very important to get an objective picture and more realistic estimates of supply and demand in cumulative volumes.

The signed accumulation mode does also work with bar volumes (not deltas), that is it considers direction of Close price move as indication of whether the bar volume should be considered for buys (positive) or sells (negative).