Hi William,
someone might shift this to the attendance forum: https://moodle.org/mod/forum/view.php?id=741
You're not the first person to notice this - there were a number of issues with the reports which were tidied up a lot recently as part of this pull request:
https://github.com/danmarsden/moodle-mod_attendance/pull/201
there is also some discussion on the issues/improvements in:
https://github.com/danmarsden/moodle-mod_attendance/issues/188
https://github.com/danmarsden/moodle-mod_attendance/issues/127
https://github.com/danmarsden/moodle-mod_attendance/issues/163
https://github.com/danmarsden/moodle-mod_attendance/issues/38
https://github.com/danmarsden/moodle-mod_attendance/issues/66
The screenshots on the plugin entry page haven't been updated with those changes yet.
Feel free to create a new issue in the attendance github tracker if there are further improvements/changes you would like to see to the reports - especially if you need the stats pulled back into a specific report.
thanks,