I guess he knows that exactly. You might got it wrong. After the extension you can stay another 180 days. Then you must leave Thailand and can reenter for a new 180 days, which can be extended also only one time for 180 days. So that’s 360 days (around 12 months) between the 2 extensions, exactly like he described it. Can be also longer depending on how long he’s staying outside of Thailand.
Thank you for the sharing your experience. To go for a border run depending a bit where you staying at the moment. From Bangkok for example you can get cheap flights to Vietnam. From Pattaya you could go by bus to Cambodia. From north of Thailand to Laos. South of Thailand e.g. Phuket it’s better to go to Malaysia …
The fine is because he missed to report his 90 day staying in Thailand. All long term visa holder are required to do the 90 day report. You misunderstood something.
The fields „Country of Passport“ and „Nationality“ are predefined for selecting the countries. This should be both selected „France“ in your case. Only „Place of issue“ has no predefined field. There comes „Embassy of Mauritius“. Maybe you made a mistake and choosed „Mauritius“ as „Country of Passport“. 🤔