Imbalanced memory usage after adding new data nodes (1 reply)

We have upgraded our cluster from 2 to 4 data nodes. However the data usage on the old nodes is significantly higher than the data usage on the new nodes.

Node 3: Data usage is 74%(194636 32K pages of total 262144)
Node 3: Index usage is 32%(85303 8K pages of total 262272)
Node 4: Data usage is 74%(194756 32K pages of total 262144)
Node 4: Index usage is 32%(85289 8K pages of total 262272)
Node 5: Data usage is 39%(102895 32K pages of total 262144)
Node 5: Index usage is 24%(65567 8K pages of total 262272)
Node 6: Data usage is 39%(102889 32K pages of total 262144)
Node 6: Index usage is 25%(65569 8K pages of total 262272)

ALTER TABLE .... REORGANIZE PARTITION; has been run on all tables.

Nodes 3 & 4 have been restarted with the --initial switch

Is there something else which needs to be done?