Tim,
I believe that is controlled by the START UP function of the ESC. The setting comes up as Auto, and then you plus or minus. Lower number slows the start up, so probably try a negative number. I use the Spin non-Pro and it is a bit different in the manual.
My understanding is that the timer allows the ESC to control that until the blinking light goes to its normal flight blink, about 8 seconds from first spin. The ESC can ramp up in that time depending on how you set the ESC. I didn't ask one of the other flyers who uses the Spin Pro how he set it up, but, his does slowly ramp up.
Ken nd I discussed this and he may try changing the Auto to Auto minus/plus. You can change the ESC start up function to Auto minus a few, and hold the plane and let it start for a few seconds to test ramp up. 10 seconds of run while holding should not harm anything, and can answer your question. Please post here if you get a result.
If you haven't tried shutting the system off yet, you can easily do so by holding the timer start button in for a couple of seconds. That will allow you to test as above.