I was editing a singing tree today based on a downloaded 1 and had all sorts of issues and I've seen others with similar ones.
Could it be possible to do 2 checks on the model data
1) Check for non contiguous/sequential numbering and highlight the last/next numbers to indicate where the breaks are
2) Check duplicate numbers and highlight duplicates
Both of these could be handy for when typos are made as it's often hard to pick in a grid of hundreds of numbers where you've missed a number, had a typo which gives you a weird channel or ended up with a dupe. The check sequence may show up some of the issues but they can be exceptionally hard to track down.
Sometimes you want duplicate numbers and sometimes you want gaps in the channels so these "tools" would need to require user input.