"Are You Sitting Comfortably?" is a 1969 song by the progressive rock band The Moody Blues. It was written jointly by band members Justin Hayward and Ray Thomas. It was recorded and released in 1969 on the Moody Blues Album "On the Threshold of a Dream".
No other band members participated in the writing of the album. 
The passage states that Justin Hayward and Ray Thomas wrote Are You Sitting Comfortably together, but never says if any of the other band members joined in writing the other songs on the album.  Therefore you cannot say that its definitely correct or definitely incorrect. 