Dear all,

a friend of mine claims that the stay in Thailand on a single entry NI – O visa can be extended easily for an other 7 days.

In my opinion it can not!

Are there any people with experience on that?

Thanks for all pit101

It is not an approved extension but they normally allow application which is not approved but allows you seven days to depart. Often a ticket out within that time period will be required.

Something I've been wondering about for some time but never asked: with this "under consideration" stamp asking the applicant to report to the immigration office again in 7 days, are these 7 days calculated from the date of application or from the expiration date of the current permission to stay?

It is 7 days from time of applying, as they have 7 days to consider your application. But in practise I believe it is often 7 days from the date your permisison to stay ends.