Had a look at the Schiphol notams today and I see what you mean. I can't shed any light on the stuff in brackets, but it may relate to the CAT3 A/B/C definitions.
From memory the Annex 10 definitions are something like:
3A is horizontal visibility down to 200m
3B is vis down to 50m
3C is 0 to 50m vis.
It's probably something to do with that. There's also something in the back of my mind about EHAM being the only CAT3C airport in Europe. I think the UK ones that are CAT3 are all 3B. I stand to be corrected
The consistancy of the NOTAM texts is also a bit all over the place. The ones I looked for were just spanning the next few days.
ST