I believe what Lurker said was that not all vessels in his campaigns are covered by NSM. So you might see a vessel or two that doesn't "act right" according to NSM standards. I've been using Lurkers 1.4 campaign with NSM and will use it with 1.5. As far as the Uboat side of things, Werner didn't adjust the sinking characteristics of the Allied vessels, so it won't work if you're planning on sinking them.
If I'm wrong on any of this (as I occasionally am:rotfl
, someone please correct me.