In Germany we have the same mess...

Actually I'm using this rules:

mkgmap:country!=* & mkgmap:admin_level2=* { set 

mkgmap:country='${mkgmap:admin_level2}' }

mkgmap:region!=* & mkgmap:admin_level3=* { set 

mkgmap:region='${mkgmap:admin_level3}' }

mkgmap:region!=* & mkgmap:admin_level4=* { set 

mkgmap:region='${mkgmap:admin_level4}' }

mkgmap:region!=* & mkgmap:admin_level5=* { set 

mkgmap:region='${mkgmap:admin_level5}' }

mkgmap:city!=* & mkgmap:admin_level10=* { set 

mkgmap:city='${mkgmap:admin_level10}' }

mkgmap:city!=* & mkgmap:admin_level8=* { set 

mkgmap:city='${mkgmap:admin_level8}' }

mkgmap:city!=* & mkgmap:admin_level7=* { set 

mkgmap:city='${mkgmap:admin_level7}' }

mkgmap:city!=* & mkgmap:admin_level6=* { set 

mkgmap:city='${mkgmap:admin_level6}' }

I don't know if this makes sense, but referring to this page:

http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative

there are 2 options for the admin-boundaries:

10 and 11 admin levels :(

So actually I still playing with this setting, maybe somebody has better rules for Germany.