Hope this message finds you well.
I am working to add SLA in Services Module and I noticed that some time periods (used in other platforms) are missed for Zabbix Service Reporting.
In my case most critical time period is "Last Month". This because usually service are reviewed in a monthly basis.
Last 30 days is useful only if you made the capture the last minutes of the month, and this only work with months that already have 30 days (not Feb or another month with 31 days)
In the attached screenshot available time period are shown in this module.