A re-entry permit (multiple or single) does not care about calendar years. It is valid from the date you get it, and keeps your current admitted to stay date alive. It does not give you any extra time than you already have on your existing visa or extension of stay. A single re-entry is invalidated as soon as you leave the country and re-enter again. A multiple re-entry is valid for the entire period your current visa or extension is valid for.

On a non O A you have one year of validity on the visa.. So within that year you will get stamped in for a year every time you leave and re-enter the country. You can exit and re-enter just before the date of expiry to get another full year of stay. But if you leave and re-enter the country after the original visa has expired, you will need to buy a re-entry permit as to not cancel the permitted to stay date you already have. If you are already on an extension of stay, from immigration inside Thailand, then you always need to buy a re-entry permit to not cancel your extension.

Okay then.. Nice to know :)

He stated that both schools ends in June 2019.. Are you saying that some schools would count that as being admitted until October?

But.. there can be a difference in when the school year starts in different schools yes

Should not matter if on the same school if the school terms is the same.

Or maybe he has the wrong info ;)

He said it was. Thats why i say it must be a mistake, either in the papers or from the IO

No, but within the same month of August.. So 4 months difference in the admitted to stay stamp seems off if their school terms is the same.

@Steve ******

that does not add up, when both families entered in August on a single entry that got extended.. The permitted to stay date is 4 months apart on the extensions.. Maybe the letters from the schools where different. Could be a typo in the letter, or a mistake from the IO. If the school terms is the same it has to be a mistake somewhere.