That would be assuming subs and mains levels are well integrated. That setup and integration is often tricky to get right case by case whenever a sub is involved and may actually be a detriment in some ways until integrated optimally.
ITs not an easy thing to do. Sometimes its best to just let the speaker designer design the sound in total and just go with it.
I heard the ls50s in a large and small room in my house.
Bass extension and overall presentation was not good in the larger room.
In the smaller room, Bingo!
Subs would have alleviated the issue in the larger room I think, but never tried, so can't say for sure other than that is usually the case when monitors and subs are married happily.