fix: use extraUsers instead of extraCapacity for unrestricted pseudo-capacity

src/Handler/Utils/Exam.hs

@@ -433,14 +433,6 @@ examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences
 
         restrictedSpace :: Natural
         restrictedSpace = sum restrictedLengths
-
-        extraCapacity :: Natural
-        extraCapacity
-          | restrictedSpace > numUnassignedUsers = restrictedSpace - numUnassignedUsers
-          | otherwise = 0
-          where
-            numUnassignedUsers :: Natural
-            numUnassignedUsers = sum $ view _2 <$> wordLengths
         
         longestLine :: Natural
         -- ^ For scaling costs
@@ -545,9 +537,18 @@ examAutoOccurrence (hash -> seed) rule ExamAutoOccurrenceConfig{..} occurrences
         optimumRatio :: Rational
         optimumRatio = ((%) `on` fromIntegral . max 1 . sum) (map (view _2) wordLengths) restrictedLengths
 
+        numUnassignedUsers :: Natural
+        numUnassignedUsers = sum $ view _2 <$> wordLengths
+
+        extraUsers :: Natural
+        extraUsers
+          | numUnassignedUsers > restrictedSpace = numUnassignedUsers - restrictedSpace
+          | otherwise = 0
+
         widthCost :: Maybe lineId -> ExamOccurrenceCapacity -> Natural -> Extended Rational
         widthCost l Unrestricted w
-          = Finite ((fromIntegral w - fromIntegral extraCapacity) % List.genericLength unrestrictedLines
+          = Finite (fromIntegral w
+                    - (fromIntegral extraUsers % List.genericLength unrestrictedLines)
                     - nudgeRatio * fromIntegral longestLine)^2 
           where
             nudgeRatio :: Rational