i have a multi-entry non b visa good for one year... i've heard that if you got to immigration before the year is up you can get a one-time 2 month extension...is that true? thank you for your time

A foreigner married to or the father of a Thai national can get that 60-day extension. Police Order 777/2551, paragraph 2.24.

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Maestro

As Maestro says only available if you are married or have a thai child, you can get a one off 60 day visa

You might be able to do a visa run the day before and get another 3 months like you can on a NOn o but im not sure if you can work on it

If you do a border run just before your multiple entry Non-B visa expires, you will receive a new 90 day permission to stay on re-entry stretching your visa to 15 months. And at 15 months you can then obtain 60 day extension on basis of Thai wife (if required).