Could you please modify the scopechangeburndownchart (or sprintreport) REST API to include the current Sum of Time Spent as well as the current Remaining Time Estimate? There appears to be no other JSON or XML way of extracting this information through JIRA's REST API.

The following URL does not provide this information:
[JIRA-URL]/rest/greenhopper/1.0/rapid/charts/scopechangeburndownchart?rapidViewId=[rapidViewId]&sprintId=[sprintId]

Nor does the Sprint report:
[JIRA-URL]/rest/greenhopper/1.0/rapid/charts/sprintreport?rapidViewId=[rapidViewId]&sprintId=[sprintId]