What about standard DDIC with enhancement category

Hi, I have a standard structure (SCRMMKT1) where I want to add a append, to include a ZZFIELD.

But the structure has the enhancement category "<b>Can be enhanced - character-type or numeric</b>"!

When I add the append, the syntax check gives the following error:

<b>Current enhancement category Can Be Enhanced (Numeric or Char. Type) is incorrect</b>

When I go to Extras -> Enhancement Category, it says in the box "<b>Selected category inconsistent with implicit enhancement category</b>" , which is Deep.

Any ideas?