EDIT: ignore all this and see next post 
So as you've noticed....velocity from bound objects doesn't transfer to particles, because particles are bound by position, not velocity...there is a workaround for this though.
Above your acceleration test, add a speed operator (set to continuous) and set both modes to 'verlet'. This will artificially assign velocity to your particles, based on the difference between their current position and their position at the last time step. Now, if your particles aren't locked to a specific place on the surface, modifying their velocity like that will also inject that same value into their motion...which you may not want. So you may need to save their original velocity before your verlet assignment and property test, and then restore it immediately after, using 2 custom property operators above and below your speed/test operators.
This can also all be simplified with a script operator, but for your purposes maybe using built-in operators is still easier. Eventually I may add 'verlet velocity' to the custom properties operator directly, so you don't need to manually construct it.
So as you've noticed....velocity from bound objects doesn't transfer to particles, because particles are bound by position, not velocity...there is a workaround for this though.
Above your acceleration test, add a speed operator (set to continuous) and set both modes to 'verlet'. This will artificially assign velocity to your particles, based on the difference between their current position and their position at the last time step. Now, if your particles aren't locked to a specific place on the surface, modifying their velocity like that will also inject that same value into their motion...which you may not want. So you may need to save their original velocity before your verlet assignment and property test, and then restore it immediately after, using 2 custom property operators above and below your speed/test operators.
This can also all be simplified with a script operator, but for your purposes maybe using built-in operators is still easier. Eventually I may add 'verlet velocity' to the custom properties operator directly, so you don't need to manually construct it.