The change of MDA to DA for non precision approach is due to the new EU-OPS 1 minima and CDFA profiles that they require(appendix new 1.430)
Jeppesen explanes how their displaying it here
http://www.jeppesen.com/download/bri...b_jep_08_D.pdf
potkettleblack are you questioning what the OCA is and why its related to a CAT 1 ILS or why your company chose to mention it in their notams?