Workflow Timing/Delay Variance

I created a Workflow last night as a test for lead nurturing.  There are 5 states although only the first 2 have been executed so far (not enough time elapsed to test the rest yet).

The issue I'm having is I tested the workflow on 2 records created at the same time but the scheduled/delayed timing on the 2 records varies significantly.  (NOTE:  my delays/transitions are in Unit=Hour to speed up the testing...although in production they would be Days)

State 1:
Action=send campaign email, Scheduled, Delay=1 Recur=0 Unit=Hour
Transition=delay 3 hours
(Intent:  workflow initiates, waits 1 hour, then sends email.  After 3 hours move to State 2.  In production this would actually be (when we change to days instead of hours):  Day 0 workflow initiates, Day 1 email sent, Day 3 transitions to next state)