@Yo***
you missed the part when we started to say "use your own funds, don't need the agent" . . . or when we said, "you have no own funds, then use the agent to front them" . . . .
in the first case, you are fulfilling the first year's extension requirements which are that your own funds need to remain in your account for the full year.
However in the second case the agent just borrows you 800,000 THB and puts them into your Thai bank account for maybe 15 minutes, then withdraws them.
Which means that during the whole year of the first extension you don't have own funds sitting in your account, which further means you are theoretically in overstay, and further means you are not fulfilling the requirements, which require the funds to be remaining in your account during the year