Right, and regen = charging. The heating function was added by popular request. I'm suggesting a tweak to save energy.
I think you meant to say don't go into a cycle of keeping the battery heated until the charging starts -- in other words, don't heat it from 7pm to 3am if my charge is set to start at 3am. From 3am onwards, heat, charge, and keep it heated.
I'm thinking a window of time, separate from charging, is needed. I may want it to charge on plugin, but don't bother heating it over night until it gets close to when I leave for my commute. And stop heating after X (settable) hours.