Start/Stop Charging Schedule by Charge Level

It would be great to be able to set the current battery level as a condition when adding a start and stop charge schedule if that's possible?

My electricity plan has multiple price levels at different times of the day. I obviously set to charge at the cheapest time (9am - 3pm) however I also don't like to have less than 30% battery level in the car at any time so there are times when I would want to charge at a slightly more expensive rate if I have less charge in the battery.

Ideally it'd be great to be able to set a schedule such as...

Start charging if: At home, At 9pm, if less than 30% current battery charge.

And also..  Stop charging if: At home, At 2am, if more than 30% current battery charge.

Thank you!