The Beatles' "If I Fell"

I listened to the Beatles' A Hard Day's Night this morning, and I noticed some interesting things going on with the vocals on "If I Fell," but I'm not sure I can accurately describe what's going on.  After the introductory part by John - when Ringo's drums and Paul's harmony come in, it's difficult to tell which vocal part is the lead and which is the harmony.  It's much more balanced than a lot of the other Beatles lead vocal/harmony pairings are.

At a few instances ("I must be sure," "Don't run and hide," etc.), they either break the lead/harmony distinction and sing the same part, or the harmonies come really close together like the Everly Brothers.  I can't tell which.  But the great thing about it is that it doesn't seem jolting or obvious.  I'm fairly familiar with this album, and I didn't notice it until now.