The Volume change result shows the change in runner volume from the original design to the optimized design.
The runner volume change is displayed as a percentage of the original runner volume.
The main purpose of the Runner balance analysis is to minimize the size of the runners, while ensuring that the fill pattern is balanced and the packing pressure is uniform. This will minimize the runner volume and, therefore, the amount of material required to make each part.
The Runner balance analysis should indicate a negative change in shrinkage (%), which means the runner has gotten smaller.