NOTE: This suggestion is for JIRA Service Desk Server. Using JIRA Service Desk Cloud? See the corresponding suggestion.
Allowing for data such as:
This is from Step 2: Defining calendars.
Working Hours in Jira Service Desk
Configure working hours in Team Calendars
Display lengthier SLA times in appropriate format (i.e. days)
Provide working hour calendars functionality that Vertygo SLA has