as long as it's valid (which it will be until your current extension expires) you can exit/re-enter the country all you want during that time and you'll get stamped back in for the expiration date you have now on your current extension of stay stamp
No problem at all, buy a re-entry permit (either a single re-entry for 1000baht or a multiple re-entry for 3800 baht) at the immigration office where you got your extension issued OR at the airport before you fly out
you can then exit the country and when you come back you'll get stamped in until your current extension expires.
Just so everyone is clear, you would be hard pressed to find WORSE advice on entry/visa/extensions to thailand than you get asking any of the AI programs out there 😮
It's because so much bad information is out there, when it data mines it uses the bad info instead (because it's been repeated so often)
Be that as it may,
In bangkok you can apply for a 30 day extension on your 60 day visa exempt entry stamp when you have 45 days or less left on your current stamp. To get a 30 day extension on a 60 day visa exempt entry you go to IT Square Laksi Plaza, you go in person. You need a TM30 showing you're registered as staying at a place in Bangkok
No need to run your stamp down, you don't lose any time applying early, they add the 30 days to your current stamp expiration date
The O/P is using the Sukothai immigration office and as he said they allow 30 days or less for extensions, so at least he knows for sure when he can go
We wish him the best of luck with his upcoming extension (y)
well at least you KNOW for sure that you can't apply until you have 30 days or less left on your current stamp 🙂 Hopefully you got the hand out from them listing the documentation requirements as well