Add "Actual Time" as option to charts among "estimated time"

It’s sometimes necessary to create stacked charts where one of options should be “actual time” but Asana allows only “estimated time”.

e.g. I wish to see actual time spent on certain type of tasks in different projects while I can do this only with estimated time. I do not understand this limitation and it’s forcing me to create custom column basically coping data form “actual time” to be able to present it.

I attach a link to a topic better explaining reasons behind this idea