Late night listening has been a go to listening period for myself on regular occasions.
To sit down without distraction when the body really rewards for being allowed to relax, is a great time to take part in a self indulgence, these simple pleasures will generate the feel good factor.
How much the system improves as a result of using the system at a time when the ambient is at its most quietest and the impact of the Lower Grid Usage on the system at this time of the evening during the playback time is an unknown, but the experience being encountered is worthwhile to keep pursuing.