Keep in mind that you need to buy oil for the application, Delo 400 suits a old school oil burner engine where HX7 will suite a common rail engine better in my opinion.
What I mean by this is the following, on the TD42 the oil will "soot" allot sooner than on a ZD30, in other words the oil will be black and filled with carbon deposit sooner. So on the TD42 the oil will be shot at 5,000km to 7,500km regardless if you use full synthetic or mineral oil. The Delo 400 just handles this better than the HX7.
On the ZD30 you dont have this problem and your oil will not soot as soon, your engine burns fuel much cleaner and the oil does not contaminate so quick. I wpuld stick to HX7 on a ZD30.