Interesting question, and one I've thought about in the past as well, but never really articulated as well as you have done.
For me, i think each line makes sense in it's own right, and a small collection of lines also make sense in many songs, but when put together I cannot usually answer "what is this about?".
For example, Tanita will say that "Men and Women" is about "how we are together", but I don't get it from lines such "And the drag past, and the walk past, and the days last long, and your eyes shine and I see mine in them, and I see myself" - which are beautiful by the way.
I think I have stopped trying to wrestle with the overall meanings of Tanita's songs because (a) I haven't got there after 18 years of listening and (b) I'm not sure Tanita sees a song as having/needing one message or concept. They are more collections of thoughts/ideas and evocations of feeling/emotion within an overall atmosphere of either/and/or playfulness, regret, pain, yearning etc.
With Sentimental, it's one of the first albums where I haven't been tempted to look too closely at her lyrics. They are clear in two ways (1) they actually make sense and the language isn't complex and (2) the feeling of the song comes from the music and voice/temper rather than the words.
With TCS, I didn't look too closely at the lyrics because I felt that there wasn't much depth in many of the songs, although the melodies were nice.
With LITC, i was still looking for direct meaning from lyrics. I think this is about the time I stopped doing that. because around this time, I got famililar with some writings from Tanita about her songs, and the meanings within them (if she was being honest). So, To Drink the Raindbow was "clarified", as was Elephant, Preyed Upon etc. etc. And, unsurprisingly, I hadn't got that exact meaning from the music/words, but could see where she was coming from and it helped.
So, what I'm thinking is that I will not puzzle too much in future because (a) her songs do carry collections of meanings but mostly are impressions/moods and (b) i'm sure clarification will come at some point.
I mean, I think we're all a lot clearer about Twist in my Sobriety's meaning after she has clarified. The idea that all these things are happening around you, yet you are almost in a trance, not reacting, not involved. A sober, inactivated state. None of the individual lines give this away, the whole collection does, but you are still unlikely to get it without a hint from Tanita.
Anyone want a guess at Heart in Winter? It's hinting at death and heartbreak, but then has that optimistic and playful brass at the end.

I'm sure others will be able to help us out
