Service downtime calulated including availability calendar

Hi,
is there possibility to set the automatic calulation for service downtime including SLA availability calendar?
In Release Workitem there is an option to input Downtime start and end datetime but it calculate without availability calendar.
Eg. service has got SLA from 8 am to 4 pm. Service Downtime is from 2 pm to 7 pm.
Time of downtime = 5 h - is is calulated by default in SCSM.
Time of downtime for SLA = 2 h.
Second subject, how you set service downtime by incident/problem? Do you use also RR ... or As incident time?
Answers
Hi @Marek_Lefek
Interesting questions here. Can you explain a little more how this is defined:
'service has got SLA from 8 am to 4 pm'
Service downtime by IR could be measured by affected service, time from creation to resolution and if the IsDowntime flag is set on the IR.
Geoff