@Dirk ********
Never listen to what a Thai consulate tells you about rules for immigration in Thailand. The consulate is run by the MFA. Immigration is run by the police. Seemingly they don’t tend to communicate well.
Your OA visa is valid for one year. On entry you will get stamped in for 365 days or however long you have insurance for.
If the last day for your visa is November 10th and you arrive in Thailand on or before November 10th with valid insurance you’ll be stamped in for 365 days.
Once the visa expires then your entry stamp is no longer “multiple entry” so in order to keep the stamp alive you’d need a re-entry stamp to keep that new date alive.