sorry sir, I'm not talking BS there, but you are. Immigrations offices aren't even dealing with visas in the first place. You're speaking with way too much confidence there.
I've already told you where the best place for advice is. It's here. For specific visa questions, the embassy is the go to place. Not immigrations.
What a bunch of crap. The immigrations office cannot give him anything useful. Here, on the other hand, is where you can find people who know the ins and outs and can think along. If that's not you, perfectly fine, but don't send people to places that won't get them and further please.
Be aware that February 7th is one day too long in your case. For a single day the 500 baht fine is normally waived, but you will still get an overstay stamp. The count works calendar day based, yielding one more day than a duration-based count would.
I think you should be fine with a third entry. Although you'll max out one stay, the one in June/July barely exceeds 30 days. There should be room for one additional entry. If they ask how many days you plan to stay, you could help your case presenting a lower number than 90.
You could also consider getting a tourist visa. Then the check of your travel history is done upfront. If the embassy is good with it, immigrations is not supposed to deny entry.
You speak of August but if you max that one out, it puts you in November. Then there's not all that much time between that one and a new entry in January. It will also matter whether your other two entries were maxed out and back to back, or not.
Either way the safer bet is to not plan that it'll work.
it's a decades outdated requirement, no one can reasonably be asked to show cash entering a country. Everyone knows that, immigrations does too. Hence why they don't enforce it. And where did you see "all these" posts? Imho it is just this one.
Did you read my story and the investigation about the supposed refused entry? It was directed not at the entrant how she came without cash, it was directed at the immigrations supposedly refusing her for it. And it turned out it was made up, she wasn't denied. The to be expected outcry in the (social) media and the headlines, it was all there.