Your ears are the best judge.
Cardas, among many others just give another perspective
Speaker Placement | Cardas Audio
Based the calculator, that distance is for a room around 8 feet wide.
Not a guide for a living space, as it encourages breathing room for the speakers, which can produce amazing results but as always-YMMV
I have my ESL's pushed way out into the room-about 7' in 26' long room.