You suggest they both lied to me? It also makes sense what they say, 500K is needed as financial reserve when you are in Thailand, why should you only need that at moment of application.
Up to now nobody was able to show where it was announced for DTV visa requirements are only temporary
No reason to ask, they are checked when they enter the country, they are checked every year at extension, and also might not travel in and out very much, so why do the extra checks? Just to check if their collegues at the immigration do their work in a correct way?
But I was not talking about actualy checks, you suggest you don't need the 500k permanently
DTV visa has no maximum number of days in a year, maybe you confuse it with the fact that when you stay 180 days or more in a calendar year, you become automatically Thai tax resident.
Practical consequences of that heavily depend on your personal situation.
The only problem might occur when IO sees the rules for applying visa were ignored and applicant did not wait for the decision, but more likely there will be no problems.