I don't think the level is stored in the area file, so that will be hard to do, without making major changes.
Object Level
Posted by Nick Gammon on Tue 31 Jul 2001 10:50 PM — 2 posts, 14,057 views.
As a workaround, you could make the level calculate based on value rather than area, since the value is stored in the area file, so cheaper items are a lower level than higher items.
Then when your wiz changes the level, if s/he also changes the value of the item, it's level will stay the same (provided you change to an appropriate value).
Then when your wiz changes the level, if s/he also changes the value of the item, it's level will stay the same (provided you change to an appropriate value).