I went in yesterday to get the Cov 19 extentsion and was charged the usual 1900 baht and 500 baht overstay 1 day. Even though I had been in the day before and the guy said that due to so many people I could come back the next day. Go in and get your Cov 19 extension on the day its due. Everyone has a different story in there.
I have used AYA van from CM .. Delivers you to Embassy in Vientiane .. And picks you up next day back to CM .. Easy, if slightly uncomfortable, sitting up, but saves heaps of hassle, and you are looked after all the way ..