If my spa is really the only main concern, having it run all day while gone and wasting $100 of propane,
Tox,
I am still puzzled..

Why do you have the spa scheduled at all?
As an example: If you have your system set up to run the pool mode say 8 am until 8 pm. If you want to use the spa at 7 pm, you just use the "V" button to change Auto to Spa and you are done.
I'd like to help, but can't figure out what it is you want to do.
Just to confirm.. To run the Spillway mode, you would be in the Pool mode and turning on the spillway mode simply causes the Intake valve to move so that the system sucks water from the pool and sends it all to the spa. The spillway mode has nothing to do with the Spa mode..
Thanks,
Jim R.