When i came to Thailand a few weeks ago. I flew into Suvarnabumi. They didnt have any entry cards to fill in. They said i dont need one. Is this normal? Maybe because i have an Elite visa?

Hi! I’m flying to Thailand on a 1 way flight with a non-immigrant type O visa. I’m worried about what I should put on the TM9 when it asks for duration of stay and return flight number. The Thai embassy I got my visa from said it was ok and so didn’t require a departing flight. I’ve also heard that people tend to not have problems as long as they have a visa, but Id love to hear any advise in this area. Thanks!