Why does BatchCubingJobBuilder2.java calculate building level in a different way ?

[you Zhuang]

In BatchCubingJobBuilder2.java, line 122:

final int maxLevel = 
CuboidUtil.getLongestDepth(seg.getCuboidScheduler().getAllCuboidIds());

Is this some more complicated?  Why not use 
seg.getCuboidScheduler().getBuildLevel());   I see this snippet at line 71 in 

CuboidJob.java