Allow difference of one in least significant digit

[newbthenewbd]

403 errors in there... Not necessarily all ready, for now a pull request to create a log :)

Metanorma PR checklist

• [ ] Breaking changes (list related PRs)
• [ ] Documentation update required (create task for this)
• [ ] External dependency introduced (documentation update need)
• [ ] Gem with native library introduced

[ronaldtse]

Let's just merge this first!