It seems to me as if one level dimension does not exceed the absolute value of 5000, the respective level_ent.min/max will stay at -5000/5000. Seems like a bug to me, too. The obvious solution is to add, f.i. one dummy entity per level that contains the information. You/ sPike has to enter it in WED manually, of course.
"Falls das Resultat nicht einfach nur dermassen gut aussieht, sollten Sie nochmal von vorn anfangen..." - Manual