Dan, taking into account my limited listening skills, I would say the second song is a 6 or 7. Understanding a song is definitely harder than understanding a normal dialogue. I took a look at the lyrics of Both Sides, Now, and I couldn't clearly understand many words I know when they were sung -- maybe because they link words in a very rapid way? Well, I am not sure why.

I've never tried to practice my listening by listening to songs. I wonder if it is a good idea. Since understanding songs are a hard task, it seems that once I am able to understand them, I'll then have reached the "native-like ear". Richard's point is really a good one when he says most lyrics are non-sensical. Sometimes I am able to understand what the singer's singing, but I doubt of my understanding since the verses, sometimes, make no sense to me.

Just to be clear... I'm not a teacher, but my language partners and italki posters sometimes ask for suggestions. And the purpose of including the Gilbert and Sullivan song was just to establish an insanely extreme endpoint to mark the top end of the scale. As I noted myself, not only are the words and language difficult, but the cultural context is extremely difficult. (I like Gilbert and Sullivan but frankly I doubt that any modern listener understands all the humor. I don't think you can even trust experts and reference sources because I have a very strong suspicion that Gilbert included as many sly double-entendres as Cole Porter and that the people who "got" them didn't write about them).

As for "Then again, I'm not a proponent of using music to learn a language because of the poor enunciation in many cases, the horrid grammar, not to mention the incomplete thoughts..." well, yes, but I'm interested in finding the exceptions... not only in English, but, for my own purposes, in Spanish, which I'm trying to learn.

Obviously, "Louie Louie" by the Kingsmen would not be a good song for English learners!

I think the problem is probably worse in English because the language isn't very musical, and singers distort the phonemes in the interest of musicality. It's not done any more, but in the 1950s and 1960s I once asked someone why musical comedy singers used such strange, opera-like pronunciation, and I was told that at that time, serious singers were actually and intentionally taught Italian vowel sounds, even when singing in English. And of course the pre-microphone tradition called for unnatural sound formation in order to strengthen the upper overtones and produce a sound that could be heard at the back of a theatre above an orchestra.

I'd never choose a Gilbert and Sullivan song as material for an EFL lesson!  It would take hours to explain the cultural references, never mind the language issues.  How about songs by the Beatles? 

Both Sides Now was popular in 1968, which might account for my not understanding the lyrics then. But then in those days the lyrics didn't really matter.

Personally, I would never suggest that one practices their listening skills by listening to that song. The lyrics are difficult to decipher and the storyline/message is almost non-sensical.

Then again, I'm not a proponent of using music to learn a language because of the poor enunciaiton in many cases, the horrid grammar, not to mention the incomplete thoughts.

I even have problems with understanding everything that is said in songs in my language due to the effects and slang which I have difficulties understanding.