private void diffOffering(ArrayList<Change> list, OffRec rec,
			HashMap<String, Object> map) {
		OffRec inc = makeOffering(map);
		if (inc.getStart() != null) {
			if (!inc.getStart().equals(rec.getStart()))
				list.add(OfferingChange.setStart(rec, inc.getStart()));
		}
		if (inc.getDuration() != rec.getDuration())
			list.add(OfferingChange.setDuration(rec, inc.getDuration()));
	}