Hi Ritu,
Yes, it's correct. You can see more here on the availability of the LookbackAPI's data:
https://rally1.rallydev.com/analytics/doc/#/manual
(The CA Agile Central Lookback API is currently in Open Preview. Changes made within the Agile Central ALM usually appear in the CA Agile Central Lookback API within 15-60 seconds).
The Data Collection for reports though run at midnight per the time of each Workspace and that data becomes available in reports after that collection has finished.
Sagi