So you're all saying we must accept songs as perfect? Not to be touched? Crazy!
Maybe you guys don't study songs like I do, but there are so many dodgy lyrics and poorly constructed parts of songs.
Randy Travis, for example, has "ruined" some of his potentially great songs by having awkward chord changes in his choruses.
I think this stems from the desire to do something different,
Different is fine...if it works1

And, by the way, I still say that "my line" adds to the drama of the story, and is not at all ambiguous!

The line "that was long before we found the box" is clearly ambiguous!
Indeed, I think all of you, who like the original line, like it for the wrong reason!
You like it because of the way it sounds!
You are dismissing the ambiguous nature of the line!
"up until we found the box" is not at all ambiguous, and it emphasises the sudden, dramatic change the family went through upon examining the contents of the box.

Again, here are the TWO lines in question:

"We all thought his heart was solid rock,
but that was long before we found the box"

That's just plainly confusing!

No,No,No! The family still thought his heart was solid rock five minutes before they found the box!

"We all thought his heart was solid rock
but that was up until we found the box"

Now, that isn't confusing! That covers everything

And, by the way Nigel. " FOUND THE BOX" in the context of the song, means " the contents of the box" Get it!

!