Allow rolled up values from sub-tasks to parents and higher to count as actual estimation as opposed to a "preview"

When estimating issues as the standard issue type level or lower, the values roll-up, but the preview values do not count as the actual estimation.

The preview still leaves the the estimate to be manually input, which could be useful, but in most cases the preview would be the accumulated total of estimated issues and is more or less an accurate estimation.

Please create a toggle-able feature that makes the preview the actual story point estimation value.