Using the following command:
"Schematic": [ {"fileName":"darkpool.ccs","falling":false,"RelativeToPlayer":true} ]

The schematic always spawns at the chance cube's location, replacing the darkpool.ccs with a worldedit based schematic makes it spawn relative to the player. This makes it seem as if the .ccs subsection of the Schematic processing doesn't check that variable or doesn't use it in generation even if checked.

.CCS File:
darkpool.zip