Is there an option to log work automatically?

[Anna B]

I'm trying  to create several automation rules and one of the nice to have features is to start logging work automatically. I.e. when the issue status is changed to "in progress" the timer starts and when it is moved to QA (an example) the timer stops.
So if I have an estimation of 3 days and moved the issue to QA on the second day - the time spent will be 2 days. 
Hope I managed to explain myself...
Thanks

[Stephen_Lugton]

@Anna B it could be due to the format of issue.original estimate.divide(28800) not being compatible with plusBusinessDays(), try adding .round, .floor or .ceil to get a whole number and see if that works

[Stephen_Lugton]

ah, you appear to have edited the question since I wrote the answer, this applies to your original question

[Anna B]

Thanks a lot, Stephen. 
Yep, I've edited the question as I've found a missing brace (as usual, the answer is as simple as that).