Yes it appears to work well for the first level. I’ve created scene layers for each year level e.g. 2001, 2006, 2013 etc. I then used each layer by creating an extrusion to the population wanted, and the base height for each layer as the previous extrusion used. E.g for 2006 I used the 2006 population for the extrusion and the 2001 population for the base height.
Can’t understand why it would give me the correct top level but not fill in the stack to be solid!?