For the ALM cumulative/lookback data. Do you happen to know when ALM calculates that data? e.g. If ALM says I had 15 story points in defined on April 8, at what time did ALM calculate the 15 story points (noon, midnight, 2am CST the next day)?
Data collection for the Cumulative Flow/Burndown charts occurs each day at midnight of the time zone the Workspace is set to.
To confirm, is it correct to say that, "if the story changes its state or points on the story changes, that change is recorded in the revision history at the time of change but the data collection for charts occurs each day at midnight."
Yes, it's correct. You can see more here on the availability of the LookbackAPI's data:
(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.
Retrieving data ...