diff --git a/lib/Lacuna/DB/Result/Map/Body/Planet.pm b/lib/Lacuna/DB/Result/Map/Body/Planet.pm
index b7a96344..14ce659a 100644
--- a/lib/Lacuna/DB/Result/Map/Body/Planet.pm
+++ b/lib/Lacuna/DB/Result/Map/Body/Planet.pm
@@ -45,8 +45,8 @@ sub sorted_plans {
 
     my @sorted_plans = sort {
             $a->class->sortable_name cmp $b->class->sortable_name 
-        ||  $a->level cmp $b->level 
-        ||  $b->extra_build_level cmp $a->extra_build_level 
+        ||  $a->level <=> $b->level
+        ||  $b->extra_build_level <=> $a->extra_build_level
         } @{$self->plan_cache};
     return \@sorted_plans;
 }