Hi Marion, The minor seventh suspended fourth is used in place of a minor seventh chord. The way in which you label a chord is determined by it's usage in a progression. Actually, it might even be called a minor eleventh it the ninth of the chord is present. For example, if the progression is: Cmin7 to an F7 to a Bb, it would be acceptable to label the chords Cmin7(sus4), F7 and Bb. The suspended fourth gives the chord a "folk flavor" not unlike a retuned five string banjo in so-called "modal" or "mountain minor" tuning. The first chords in Scarborough Fair might have been labeled a minor seventh sus 4 but a more correct designation would be a minor eleventh since in contains the ninth.In short, it label depends on how the chord is used.
Frank