I don’t have any science to back this up, but from personal experience doing efforts on the way in makes me tired for the rest of the day and the way home a slog.
The other way around I feel energized during the day and in the right frame of mind on the way home.
Doing FTP or even VO2 work whilst in a slightly fatigued state is gonna cause all sorts of good stuff to happen. It’s the same as doing efforts when 2,000kJ into a ride.
This commute for example featured a 13-14 minute effort @ around best 20 minute power having already ridden 3 hours of endurance (2 hours AM, 1 hour PM) prior to the effort.
Paging @brendanhousler to come through with the science!