Did you notice we never got details where he walked the second 500 miles?
He may walked in one direction. Then he found out she lives next to him and walked the whole 500 miles back!
His goal was "just to be the man who walked a thousand miles to fall down at your door" so it's not impossible he just walked 2000 laps around the block she lives on.
I had the same problem with "Single Ladies" by Beyonce. Instead of "Ladies" I heard "Legs" So it was a song about people losing a leg because they got careless and didn't show appreciation. So now they are on the look out for new ones.
Not long ago i heard the Theme from one of my favourite Animes as a child and it was just one word I sung wrong but theat one word ruined the song for somehow.
I'm still disappointed about when I found out that one Soul Coughing song wasn't about con men: "You get the angles, and I'll get the rest", but the lyrics were actually "you get the ankles, and I'll get the wrists"
Fun fact: all the imperial units are now fixed on the SI system. Meaning that their formal definitions use SI units. So it's literally just SI with extra steps.