KevinD Ah - I think we've misunderstood the requirements. We've implemented a snapshot mechanism that snapshots charge rate prior to charging and sets it back at the end of a charge slot.
I think we will need to add support for charge rate into the Agile charge window.
We can't use every user's current charge rate for Agile slots, as some (or most) expect it to be max, due to the 30 min slots. We don't want to change that default behaviour.