diff --git a/src/Handler/Utils/Exam.hs b/src/Handler/Utils/Exam.hs
index 844919ed2..205e0f94c 100644
--- a/src/Handler/Utils/Exam.hs
+++ b/src/Handler/Utils/Exam.hs
@@ -197,7 +197,7 @@ data ExamAutoOccurrenceConfig = ExamAutoOccurrenceConfig
 instance Default ExamAutoOccurrenceConfig where
   def = ExamAutoOccurrenceConfig
     { eaocMinimizeRooms = False
-    , eaocFinenessCost  = 0.2
+    , eaocFinenessCost  = 0.1
     }
 
 makeLenses_ ''ExamAutoOccurrenceConfig
@@ -467,7 +467,6 @@ examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences
               , Just maxA <- nsA ^? _last
               , Just minB <- nsB ^? _head
               = let common = maxA `lcp` minB
-                    mayRange' = mayRange . max 1 . succ $ length common
                     suffA = CI.foldedCase <$> drop (length common) maxA
                     suffB = CI.foldedCase <$> drop (length common) minB
                  in if
@@ -495,9 +494,10 @@ examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences
                                  = Just $ c' : cs
                                  | otherwise
                                  = go cs
-                        in (occA, Set.insert (ExamOccurrenceMappingRange minA break') . Set.map (ExamOccurrenceMappingSpecial . take (max 1 $ length common)) . Set.filter (not . mayRange') $ Set.fromList nsA) : accRes succBreak ((occB, nsB) : xs)
+                           commonLength = max 1 . succ . length $ minA `lcp` break'
+                        in (occA, Set.insert (ExamOccurrenceMappingRange minA break') . Set.map (ExamOccurrenceMappingSpecial . take commonLength) . Set.filter (not . mayRange commonLength) $ Set.fromList nsA) : accRes succBreak ((occB, nsB) : xs)
                   | otherwise
-                    -> (occA, Set.map (ExamOccurrenceMappingSpecial . take (max 1 $ length common)) $ Set.fromList nsA) : accRes prevEnd ((occB, nsB) : xs)
+                    -> (occA, Set.map (ExamOccurrenceMappingSpecial . take (max 1 $ maybe 0 length prevEnd)) $ Set.fromList nsA) : accRes prevEnd ((occB, nsB) : xs)
               | null nsA
               = accRes prevEnd $ (occB, nsB) : xs
               | otherwise -- null nsB
@@ -506,7 +506,7 @@ examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences
               | Just minAlpha <- Set.lookupMin rangeAlphabet
               , Just maxAlpha <- Set.lookupMax rangeAlphabet
               , minZ <- fromMaybe (pure minAlpha) prevEnd
-              = let commonLength = max 1 $ length minZ
+              = let commonLength = max 1 . succ . length $ takeWhile (== maxAlpha) minZ
                  in pure (occZ, Set.insert (ExamOccurrenceMappingRange minZ $ replicate commonLength maxAlpha) . Set.map (ExamOccurrenceMappingSpecial . take commonLength) . Set.filter (not . mayRange commonLength) $ Set.fromList nsZ)
               | otherwise
               = pure (occZ, Set.map (ExamOccurrenceMappingSpecial . take (max 1 $ maybe 0 length prevEnd)) $ Set.fromList nsZ)