It's still sort of a sample size of one, though. This content would have been more effective if you had an analysis of some factor that measured your hypothesis

It's still sort of a sample size of one, though. This content would have been more effective if you had an analysis of some factor that measured your hypothesis (length of posting, salary range width) and showed the correlation with conversions. Then this could have been an illustrative case study backing that up. Even better would be the results of the changes, maybe offer for free to turn this into a junior and senior postings and see the difference multiple posts with narrower ranges makes. The holy Grail of data science is solid math foundation, benefits your clients (more apps), benefits you (more revenue, higher satisfaction), and demonstrates your effectiveness with data and willingness to continually improve.