wait THIS SOLVES EVERYTHING!!
I went back to episode 16 and I missed this! Azusa said there was a Fermata which means (hold/pause)
for example
it means to hold a note/ pause then go back to the phrase with normal tempo. it happens close to an end of a song so (giving it a dramatic effect)
pretend this sheet music
E, E, E, C 
(on top of that C note) , E
this means you neeed to hold that C for however long you want it. so it would sound like this
E,E,E CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC, E
U&I has a Fermata at 3:55 - end , Gohan has a whole note at the end not Fermata.
The fermata is marked above the note or rest to be held meaning you would need to hold this C note (with any given time you can resume back into the song)
solved
that one word that i missed completed the puzzle !!"
Fermata "
IT IS
U&I
3:56 is the Fermata (there holding that note as long as they can which gives it that fade) then goes back to normal tempo
Im guessing she could of made both songs, but for sure U&I