Calculate energy costs with off-peak and on-peak tariffs?


I have monitored each appliance and circuit in my house which are now displaying in Grafana with InfluxDB. At the moment I have each appliance in a bar graph representing cost in dollars. I have realised this is inaccurate has my electricity provider charges DOUBLE ($0.6/kw) between 4pm-10pm. Is it possible to show calculate this and show both tariffs in a staked graph?
I made a mock up in photoshop