Ravel's Le Tombeau de Couperin

Someone has this score checked out for a long time so I guess I'll try to analyze this piece by listening alone. It seems to be symmetrical phrases with an IAC followed by a HC. Then there is another IAC and HC. This is very strange. I would call it a parallel double period but the 4th phrase ends on another weak cadence instead of a PAC. I'm not sure what it is then. I think it goes into a developmental section and then returns to the original A. The rhythm changes in this B section. It feels like it's floating because the melody doesn't fall on the beats. It's constantly changing tonality. The big B section just elaborates the A getting a fuller density and broader range including bass chords. It also grows in dynamics. Then the A section returns. I think because the A section is so long and contains repeated A sections that make it sound like rounded bianary forms that this piece is composite ternary form. The end of the piece fades away with an extended cadential section and turns and scales that sound like dandelion whites drifting through the air to the ground.