EUREKA !!
I tried changing the 560 ohm resistor to 470 and also 390 ohms. Neither change had any effect on the Input pin voltage.
Next changed the 10K pullup to 2 x 10K in series, to make 20K resistance.
Before change :
On = 1.73 v
Off = 4.65 v
After change :
On = 0.16 v
Off = 4.62 v
Thank You to all for the guidance and suggestions.