In my experience far too many speakers are not given the luxury of a decent break-in period. Even at some dealers, brand new speakers are being used for demo purposes.
2,3 or 400 Hours are not unusal for a speaker to really come on song (pardon the pun).
Since I got my new speakers in Feb. I have definitly noticed them going through stages of improvements over the past months.Like loosening up.
I am not sure about running in for a second time though.

Peace

Bernd