PWM value from slider is way off. Need help with it

I have esp8266 with a mosfet board. I am putting 10vdc (10.35 actually) into the mosfet board. When the slider in HA is at 1%, it receives 0.008vdc. That is fine. When i move it to 2%, it does not move. When i make it at 3%, the output voltage is 4.8vdc. HOW? When I move it to 50%, It is at 6.3vdc and 75% is 8.4vdc with 100% being at 10.3vdc.

How can I adjust this to be a lot closer to the proper values? With a 100 % at 10vdc, 50% should be 5vdc and 25% should be 2.5vdc. Hell at 3% it should be 0.03vdc.