The online application is also likely to be rejected if there is no TM30 filed or if the 90 Day Report is for a different address to that of the last TM30 files, you will be instructed to attend Immigration.
To be fair I'd bet that the Immigration Officer is totally unaware that the TM6 may be returning as it is currently just a proposal being discussed within government circles inclusing a few very high ranking Immigration Officers and officials. The masses of ordinary Immigration Officers will know what will be required when they need to.
that is not a plan to stay long term in Thailand, you will very soon be denied entry for abusing the Visa Exempt system and not getting the proper Visa which you obviously qualify for as you already have one
Part of the 800k is only "dead money" for the first year as, for the second and all subsequent extensions, the 65k income transfer method can be used. A small price to pay for indepencence and legal status.