if anyone is going to be using an agent it would be better to use one that has a better understanding of the process and can explain it better than the crap these people are sprouting
and one of the main reasons people resort to agents like this is their claim "We can provide the funds to support the application" and if you want to go down that path then thanks very much, this is why the financial requirements keep getting made more difficult - it doesn't stop the agents playing games with bank finds it just makes it harder for the legitimate applicants
I am not familiar with an O-B visa (perhaps MFS can provide more details) but 12 month "retirement extensions" talked about in the article are designed for people who want to stay in the country long term to enjoy their retirement - hence their name, they are not designed for tourists who want to stay a few extra months on their holiday
having said that however if your plan is to travel to Thailand multiple times each year for extended periods then the Non O-A "retirement visa" may be your best option to exploit
one of the first concepts to grasp is "long stay" as applied to a visa - tourist visas and Non O visas are "short stay" and extending a permission to stay based on these visas currently does not require insurance even if the extension is for 12 months, Non O-A and Non O-X visas are "long stay" and extending a permission to stay based on these visas currently does require insurance
the second concept to grasp is visa validity, initial permission to stay and entry count - typically a Non O visa issued in Thailand or overseas is valid for 3 months, is single entry, and grants an initial 3 month permission to stay, typically a Non O-A visa issued overseas is valid for 12 months, is multiple entry, and grants an initial 12 month permission to stay on each entry
the third concept to grasp is the funds requirement - typically to do a 12 month extension of a permission to stay based on a Non O visa issued overseas or to obtain a Non O in Thailand and to obtain a 12 month extension of a permission to stay based on that visa you must prove 800,000 Baht in a Thai bank for a "seasoning period" (2 months for initial application, 3 months for extension) and the funds must still be in the bank for the next extension or satisfy the requirements for monthly transfers for 12 months, typically to apply for a Non O-A visa issued overseas you must prove the equivalent of 800,000 Baht in a bank in your home country (and some other requirements), to obtain a 12 month extension of permission to stay the funds need to be in Thailand, and you need insurance, but you can just go home and apply for a new Non O-A visa to avoid this
so if you really want to retire to Thailand then a Non O visa obtained either at home or in Thailand is your best bet, but if you want to travel to Thailand for extended periods for almost 2 years then the Non O-A visa acquired at home may be a better option