Report Builder : Work Item's "Estimate" field and its "Correction Field"

I have created a report in Report Builder that shows the "Actual Work" for an iteration versus the "Planned Work".

The underlying SQL shows that the "Planned Work" information comes from [dw].vw_request.planned_work

This is normally the "Estimate" field on the Work item's Overview tab. e.g. 90 hours

But if a user subsequently enters a "Correction" ,e.g. 30 hours, in the Work Item's Overview tab then Planned Work becomes 30 hours.

I want my report to show the original estimate of 90 hours.
Is there anywhere in the [dw] database that shows this information ? because  [dw].vw_request.planned_work is now showing 30.

Thanks

              Peter