Re-balancing of RING does not level up my objects in old devices

Hello,

I have a question related to balancing swift objects across devices added to the ring.

I have Swift setup which initially created with 2 devices in it (weight 100) and partition power 12.
These devices now started filling up to its capacity (~90% of its size).
So now I added 2 new devices (weight 100) to the ring and performed rebalance.
The ring shows me all new configurations with correct partitions mapped to each device.

But even after running ring rebalance command I do not see my objects are balanced (level up) to the newer devices.
(i.e. older devices still consume 90% of space, while new devices are empty)
So do I need to perform any additional action (run object updater once) to achieve this?

Thanks,
Tushar