Hi petemurray,
If you set schedule in the 'wait for' tile, you must met scheduled day firstly, then 'wait for' duration will begin.
What does it mean?
Depending on your screenshot, if the start date is "Wednesday" or "Thursday", it will first wait until "Wednesday" or "Thursday" and then wait another week before moving to the next action.
For testing, i have created two customer journey(Today is thursday):
(1)If you set Thursday:
Moved to the next stage after one hour

(2)If you set Wednesday:
Despite the fact that an hour has passed, there will still be no change
