Now that you mentioned PEF. That's another song that contains chordal variation. Like you said, the "won't let me down" has a Bsus4-B at some point and a F#m(7) - B at some point. Lyin' Eyes has some variation in the melody every time it gets to "and your smile". In the first verse in New Kid In Town the chords go from I to V, but in later verses it goes II-V, II-V instead of just V.
No matter who wrote the song (or that particular part of the song) there often seems to be some variation in how the chords go - very small variation. From their first album to The Long Run. So I guess it was Glenn who wanted to add that extra color.