I call that last point "fun with percentages." And I find that to be applicable when there is a low total number of people who are included. I am not so quick to debate David's information in his post; and to be open and honest, he and I engaged in lengthy disagreements in the past, based on subjective grounds. By that, I mean whether I personally was happy with a station going away or not. The outsiders have emotions towards these situations, or else we wouldn't be here discussing a format flip. For the insiders, this is a career. Being on a board like this is essentially "talking shop." Doesn't mean I won't disagree and question statements/information, the same as you are doing here.
Back to why I don't question the information David shared, first the industry where I work, then my theoretical/conceptual understand (and beliefs of David's information):
In my career (education), I come across schools that have low student populations (alternative schools, sometimes charter schools, therapeutic schools, etc.) State testing loves to use percentages in their reporting. I've seen therapeutic day schools where they talk about 50% growth, success, performance, etc; only to find out that a grade level in question had four to eight students. Therefore, I need to quickly mine that information. It's fast to find, but if I saw that 50% and moved on, I would be grossly misinformed. This is where I agree with the purpose of your inquiry.
With David's information, we don't have a demo cited. However, I need to ask of what benefit does David gain in embellishing the 30% to 50% of increased listenership when 92.3 flipped to the WINS simulcast? In full context, this is a message board with an overall low participation rate of outsiders from within the target market. To be anecdotal for a second, I'm not in New York's listening market, but rather in Boston's listening market. This event interests me, so is why I engage in this discussion. Furthernore, to access either WINS or the alternative format, I go to the same app. There was no change for me. With insiders, I still question what David would gain. Audacy isn't looking to unload WINS-FM. There isn't an insider who is on here claiming that numbers are being fabricated to increase WINS's monetary value. And, where would an insider go to gather information that is pertinent to the buisness end of this flip? I don't think they are coming here for that. Finally, it's Audacy's property to what they want with (regardless of how anyone feels about it). So David's information really doesn't impact whether the station stays all news or flips to another format.
Therefore, the above logic leads me to believe that David gains and loses nothing from the information he posts (outside needing to omit specific information due to any non-disclosure clauses he has with his work). Added, we are discussing the number one market. I would find 30% to 50% of a specific audience to be a large enough number to warrant the validity of the information. I don't foresee David really meaning an increase of 30% to 50% of students at Columbia University who are taking Sociology courses. However, a good researcher does question who was included in the population, so your question is spot on. I just am not as inquisitive to rationale behind the omission of the population included ("are the numbers being embellished by focusing on a small population?"). I'm more intrigued as a "data dork" on the grounds of general interest in knowing more ("30% to 50%?!? Who are the people included in that?").
I do get the subjective stance though. Audacy sold the rock station that I enjoyed, to EMF. My posts on that matter were subjective. Honestly, since subscribing to SiriusXM, I now subjectively observe that the station was not to my subjective standards of what I get from various channels on satellite. But back then, it was. This is why I say to outsiders that if you want the broadcast radio feel (DJ interaction and not like it's a Jukebox that your phone or computer are playing), then the streaming apps are free and you can listen to preferred content on stations beyond what's available on the AM/FM bands in New York, and even local stations that aren't available in certain parts of the market. I'm not even saying to ditch FM stations for satellite. That's what I chose for myself. But to be honest, I ditched AM/FM before I had unlimited data on my cell plan. My listening for years before was music saved onto my device and a weekly rotation of preferred and downloaded podcasts.