There are 3 different options to meet the financial requirements for the 1 year Extension of Stay based on marriage with a Thai female. (AKA marriage visa)
1. 2 months prior application date a minimum of 400.000 Thb in a Thai bank account on your name only.
If multiple account holders the money is divided by account holders.
2. an Affidavit of income of at least 40.000 Thb from your Embassy in Thailand OR if you Embassy does not provide this service:
at least 12 months of foreign deposits of minimum 40.000 Thb into a Thai bank account on your name.
3. If you work inside Thailand, the work permit, minimum salary of 40.000 Thb showed by 3 months tax and sso payments for you as well as needed staff for work permit.
Foreign ladies married with a Thai male do not have financial requirements.
If you apply on-line for the Non Immigrant O visa based on being over 50 years (aka retirement visa) OR for the Non Immigrant O-A (aka retirement visa) or O-X visa (aka retirement visa) , your wife and your son (if he is younger than 20 years) can apply for this type of visa using the same on-line system
The METV get 60 days, extension of 30 days and travel abroad
OR
get the Single Entry Non Immigrant visa, get 90 days, apply for the 1 year Extension of Stay and when stamped in passport the Multiple Re-Entry Permit.
As it is well know, some Immigration Offices are more lenient than the other. In your case it seems you always travel into Thailand and stay at the same address, house in your wife's name.
Immigration has that address on file and informs you that you do not need to visit them each and every travel to do this report again.
Be thankful OR if you really wish to follow the letter of the law, go to the website, make an account and make a report within 24 hours after coming home.