Since we have had inspections on attendance. For our KS5 students we were told that AM/PM marks must be available for these students regardless of if they are Timetabled for that time or not.
Experience on working on other MIS, you were able to set earliest mark and last mark to copy over too AM/PM marks. E.g student in sixth form is required to be in from P3, once they are marked in for P3 that mark is recorded onto AM register. Similar to PM the last mark of the day copies over to PM.
I know SIMS/Bromcom/Arbor are able to do this.