They are somewhat consistent. The ‘normal’...
MK - Wed PM / Fri AM
EP - Tue PM / Thur AM
DHS - Sun AM
DAK - Sat AM / Mon AM
...pattern is what’s on the schedule more often than not. BUT, there can always be exceptions. Some runDisney races tend to jumble up the schedule. Some holidays or other events can mean some movements. Disney can announce special runs (like the current Extra Extra Magic Hours) around new land openings, promotions, holidays (like Thanksgiving week daily EMHs at DHS), etc. You can have times (like this Oct) where no MK PM EMHs were schedule at all, for unexplained reasons.
So stuff can interfere with the ‘pattern’ above at times.
And maybe once Disney’s multi-billion $ investment in SWGE is complete they’ll someday add back DHS PM EMHs to the rotation. But I digress.