The proof for the previous year is only needed when changing from the 800k baht option to 65k baht of income.
If you wanted to avoid the proof you leave and re-enter the country without a re-entry permit and get a non-o visa to start all over again using the income option.
Immigration will check to see if you complied with requirement to keep the 800k baht in the bank for 3 months after you last application and then 400k baht for the remainder of the year. If not they would not do the extension using he 65k baht income option.
It can be done online, by mail or in person.
The online report has a space to enter your new arrival date. Immigration can confirm it by looking at their database that will show your most recent entry.
No if you enter your new arrival date when completing the application online. Immigration would approve it if you have a new arrival date and will be the report 90 days after arrival within the 15 day window to do them.
Some might do it if is a government pension. The US embassy might allow you to do a affidavit as a self certification of it.
A notary public can also do it and then have it certified by the Department of Consular Affairs of the MFA.
There no longer a requirement to submit a new TM30 report after entering with a re-entry permit for a extension of stay.
New regulation dated June of 2020.
It appears to be a certification of the proof of insurance you present to immigration that it is true and correct.
It is bit vague though in the wording. It may require a immigration office to confirm what is required.
You must be entering something that is incorrect to rejected on the new site. What does the rejection email you get state for the reason? Most are for not entering your address correctly.
It is a non-o visa that will be valid for 3 month and will allow one 90 day entry.
The will not do a multiple entry non-o for being the parent of a Thai.
Previously the consulate in Penang would do a multiple entry non-o visa with financial proof.