Absolutely true. I don't see them as the same.I'll give a long-ago duopoly example. I interned at a group that had 5 stations in our Hemisphere's largest market. One was MOR, one was ranchera, one was tropical. But two were Top 40.
Huh? the difference was that one Top 40 played half songs in English and half in Spanish while the other played all Spanish Top 40 hits. There was 50% overlap, but different audiences.
So even if a format has the same name, the execution and playlist differences make it a different station.