As I don't know the name of your live city, I have to guess here, but I don't think you're using the model correctly. Regular squad size indicates you're somewhere in chapters 12-16; T value, assuming done correctly, points to chapter 15. With that, V value is definitely incorrect, you're likely forgetting research expansions (V = base 6 + province expansions + research expansions). In chapter 15 you've likely placed up to 45-47 research expansions, for real V being about 106-108.
With that setup (fairly common for chapter 15), I definitely don't believe actual SSSo - you're likely looking at
enemy SSS (SSSe) rather than SSSo (own) at 1st encounter. You actual SSSo in this case would be about 2718, and if you plug in updated V you may find out that you're much closer to your actual SSSo
Unless, of course, you're indeed running chapter 15 on half the expansions than the most compact chapter 15 cities that I've seen. In this case, I am definitely interested in your data
That's a known thing (to me), the formula is not that close (relatively speaking) for the tiniest of cities, and your beta city is as small as they get to get Spire access.