Can I visit immigration early to get my Non-B extension approved before my business trip?

Not all that weird of a case, but you're sure gonna mess yourself up leaving the day before your under consideration stamp comes up. That means you'd cancel everything you have and have to start all over with a new Non-B and then another extension.

OR

You can slog on out to the immigration office BEFORE you need to leave and talk to the officers to see if anything can be done. There are three possible scenarios,

1 - they can 'close the loop' on the under consideration stamp early and you get it done before the date you are to fly out (AND you buy a re-entry permit right after they ink the extension into your passport)

2 - they amend the under consideration stamp another month (cross out the date and add another 30 days on it) meaning you come back on that date to get the extension inked in (AND meaning if they do that you buy a re-entry permit so you can get back in on that stamp) <- I HAVE seen them do this in special situations but it is rare

3 - they can't do anything and you lose what you have (the Non-B and the under consideration stamp) meaning when you come back you start all over again from scratch

The ONLY people who are going to tell you what's what are the officers at the immigration office where you applied for that extension SO take someone from your employer and slog on out and ask them., Have the proof you're flying out on the 16th and when you're comin' back to show them why you have a "special situation".

Face it they'll do one of the three choices I outlined.. Hopefully for you it's choice 1 or 2, because choice 3 starting over isn't gonna be all that much fun

You can go, but from experience your documents may not be sent back in time. If you have an urgent need to travel before the under consideration stamp date, then this question needs to be raised through the Immigration office where you initially applied.

Never heard someone got an under-consideration stamp closed earlier. All you can do is go to your immigration office and ask, see what they would say. The worst thing they can do is say no, you come on that day or you lose your extension. Then you have to start the whole process from the scratch all over again.

Your application for the one year extension of stay on your Non B is STAMPED UNDER CONSIDERATION...

You are instructed to return to the Thai immigration office on August 17th.

Ask your Thai immigration office if you can get the One year stamp earlier than August 17th.

AND IF you leave Thailand while it's UNDER CONSIDERATION... and return BEFORE August 17th

Be sure to have a RE-ENTRY PERMIT in your passport BEFORE you depart Thailand.

Apply for re-entry permit