Can I get my final extension stamp a day early or what happens if I'm late in Thailand?

The user is seeking advice about obtaining the final stamp for their one-year marriage extension in Thailand, which is due on March 28th. They are concerned about not being able to make it on that date and are inquiring if they can get it one day early on March 27th or what the consequences would be if they are five days late. Commentary suggests that while there is no monetary penalty for being late, there is a risk of having the extension application canceled if not completed on time. The best course of action is advised to be arriving on the 27th to discuss options with the immigration office.