Hi @DamianoDB,
The option of finding the time still in status is somewhat described in a colleagues community post here - How to calculate Days in transition status including the time in current status.
The approach of subtracting the work hours spent in a specific status might work if the issue was in that specific status once or twice. You might then separately calculate the time difference for to/from FIRST timestamp and, if required, to/from LAST timestamp.
However, if the issue is going into the undesired status more than twice, the rest of the cycles cannot be addressed clearly. Generally, that time might be found via the measure “Workdays in transition status”. Still, that measure would lack the precision of lunch breaks.
The next level of complexity would be to create a JavaScript that would scroll through the issue changelog and calculate the business hours spent in desired statuses, considering the lunch hours. That script would need the public holidays fed as an additional argument, though.
You might see a simpler option here - Sum DateDiffWorkhours on a specific status - #2 by oskars.laganovskis
You might then try to adapt the code for the workhours to also handle the lunch break. This might not be an easy task, yet not impossible.
Regards,
Oskars / support@eazyBI.com