Understanding Rates Chart

[Stealthbird97]

Hello

Maybe I am completely missing something but the Rates Chart is confusing me.
On the wiki page which explains the rate chart https://springfall2008.github.io/batpred/web-interface/#charts-view
it says

Rates - Shows historic and future import and export rates along with historic hourly and today pence per kWh so you can see where you have earned or spent the most on electricity during today

So, Import and Export are obvious and I have no problem with. It's showing my import rate (Octopus Agile), and Export (None).
What is confusing me, I really do not understand what "Hourly p/kWh" and "Today p/kWh" is.
My assumption was these were the effective average energy cost for the hour, and the average cost for the day at that time. However, looking at the graphs makes me doubt this.

Today has been a pretty poor day for solar generation so I have been importing all day, including at night where there is no generation but the import rate is cheap.

Take the period from 00:00-03:30. My battery was charged from ~30% upto 100%, Grid supplying the load, no battery discharge, and no solar charge.
So why is the hourly p/kWh and Today p/kWh well over 30p when the import rate is 10p?

Some graphs if they are any use.