I would like to calculate the difference between Original Hours Estimated and Hours Spent for tickets in the resolved state up to and including the current time period. This should work for all nested levels, so it is calculated for all members of an epic, sub-tasks and the parent ticket, etc. I have tried multiple scenarios, with descendants, childer, etc but it does not seem to aggreate the data properly.
I noticed that you already have contacted eazyBI support directly about the question and proceeded with the report.
Still, I will answer the general part of the question.
If you use Issue dimension Epic hierarchy, measures are calculated on all nested levels (project, epic, parent, sub-task) automatically. This behavior applies todo standard measures, as well as custom measures if correctly build.
There is a default measure “Remaining estimated hours” that calculates remaining estimate (original estimated hours - hours spent). If you maintain estimates and remaining estimates in Jira, then this should show the difference.
To get values only from resolved issues, add, in Pages, dimension “Resolution” and select “Resolved” (or, if you have several valid resolutions, then select them all).