For the past year Ive been reporting by mail to BKK. (After being advised by Nong Khai, not to send to them).

My next report is due just before my annual extension. I still do the extension in NK as it must be done in person and the atitude there doesnt bother me.

I believe I will recieve my notification slip back before I go for my extension, but if not, would it be a problem if I dont have it when I go to NK?

Is a notification receit nessesary to get the extension?

Also, when doing the extension, is there also a 7 day before-after rule, or does it have to be done before the date?

the extension can be done 30 day before the date......but not after the expiration day ( overstay)

The 90 days report has a 7 day before/after rule.

The extension can be done any time within the last 30 days of your stay.