BMC Blogs published best practice for creating SLA and one of it is also our challenge with measuring in SDP.

Here's the section in  https://www.bmc.com/blogs/five-best-practices-creating-slas-itsm-environment/

#5: SLAs should account for usual and unusual exceptions

It’s as important to define where the SLA doesn’t apply as where it does apply. Your SLA should define any usual and unusual situations that will hold up IT service processing. Some SLA exception examples might include:

• All orders will be released within one hour of receipt, except for Sundays between 1:00 AM and 4:00 AM when system maintenance is occurring.
• New computers will be configured and delivered within five business days, except for weeks where a holiday occurs. Additional days will be needed when a holiday falls within the delivery period.
• New users will be added to the system within one day of a completed new user form, provided management has approved adding the user. It will not be considered a service level miss if a new user request has been received but management is slow in approving the new user.
• SLA targets will be temporarily waived in the event of a local or regional disaster affecting service, including but not limited to fires, floods, earthquakes, extended electrical or network outages, etc.

How do you measure these exceptions in SDP?