Please, help with translation

[Zikomat]

I have recently made an extension to my tourist visa. Today I paid an attention that there was some additional stamp in red which I never saw before. I would like to know what it means. Thanks. (See photo below).

[KhaoNiaw]

I think it shows that you actually extended after the expiration date but this was because it expired on a weekend or holiday so allowance was made. 

[Zikomat]

Just now, KhaoNiaw said:

I think it shows that you actually extended after the expiration date but this was because it expired on a weekend or holiday so allowance was made. 

Thank you!