Jomtien immigration - congrats. You have to report your address via a TM30 each and every time you come back to Thailand, even if you are staying in the same place as before. All has to be done 72 hours within your entry, or get a nice 1,600 baht fine. If you don't need to do anything at immigration then you don't need to worry about a TM30. If you do, then welcome to the fun of TM30 each entry into Thailand.
You've gotta love Jomtien immigration, you can only do extensions one business day prior to stamp expiry too. I've wasted two trips there already and will have to make a 3rd trip one business day before stamp expiry.