I've seen just as many people reply Refit Cruiser to this answer as Assault. I'm not sure there's ever been an answer from a dev. I can't find anything from Dstahl about it on the forum. Perhaps one of the other devs answered this, though.
Thank you. I've started wondering, because more points in Assault Cruisers doesn't seem to raise my Hull stat as it should. Though that could be, because I also spent points on all other cruiser skills and might have hit a cap.
EDIT says: I just thought what the hell and spent points on one level Cruiser Retrofit and THEN my hull stat did rise. Will have to respec now but at least now I've got the answer.