You are looking at the ramifications of having a choice in power providers.
Separate the on-peak and off-peak numbers.
It appears that there is a step change once you pass 218 kWh and then again 345 kWh (218+127)
The combined and decoupling charges both seem to also have step changes at 787 kWh
This basically says that once you get to a certain amount of energy, your price changes. But odds are that your normal usage already took you into the high tier, so you can ignore the lower ones.
So On-peak = $.144438+$.073019+$0 + fixed costs
Off-peak = $.0 + $.073019 + $.0 + fixed costs
Incremental fixed costs = $.013308 + $.000405
On-peak $0.23
Off-peak $0.09
If my math is correct.
You evidently have chosen a rate with on-peak and off-peak components. You may want to call CPL Customer Service for more information.