?? Bar number's don't change due to tempo changes?? 12 bar blues is 12 bars no matter how fast or slow you play it.
I realize the bar numbers don't change due to tempo changes.
But the bar numbers
displayed in your DAW as the audio file is playing can be misaligned with the bar numbers shown in the sheet music.
The notes in bar 12 in your sheet music (the truth) may or may not be the notes being played when the cursor of your DAW passes into bar 12.
One easy way to see this is if the audio file contains a 2 bar count in when the sheet music has no such count in. The DAW
as it plays the audio file will tell you that the music starts on bar 3 but the sheet music says the music starts on bar 1.
3-1=2 So you have a discrepancy of 2 bars.