Hello, with my recent purchase GMF-1600 was a FSN OFA Attachment you can see here:

FSN OFA Professional Systemzubehör Oberfräsen | Bosch Professional



This is 70Eur attachment marketed as Professional.

The problem is with very bad tread quality used as "Professional" adjustment for position on a rail.

You can see the photos that show the quality of the thread:

Photo 1
Attachment 228612

Photo 2
Click image for larger version. 

Name:	fsn-ofa problem2.jpg 
Views:	0 
Size:	111.7 KB 
ID:	228614

Video see the wobble for yourself:
https://www.youtube.com/watch?v=lzvv...ature=youtu.be