--- a/UnitConverter.st	Mon Sep 18 09:07:02 2017 +0200
+++ b/UnitConverter.st	Mon Sep 18 11:01:32 2017 +0200
@@ -647,7 +647,6 @@
     (pairsAlready includes:(sourceUnit->destUnit)) ifTrue:[
         ^ self noConversionFrom:sourceUnit to:destUnit.
     ].
-    pairsAlready add:(sourceUnit->destUnit).
     
     sourceUnit isSymbol ifFalse:[
         s := sourceUnit withoutSeparators.
@@ -676,6 +675,8 @@
         ].
     ].
 
+    pairsAlready add:(sourceUnit->destUnit).
+
     "/ first, get rid of scalers ...
 
     u := self unscaled:sourceUnit.
@@ -889,7 +890,7 @@
     "
 
     "Created: / 17-09-2017 / 10:11:40 / cg"
-    "Modified: / 18-09-2017 / 08:39:15 / cg"
+    "Modified: / 18-09-2017 / 11:00:41 / cg"
 !
 
 fileSizeBinaryStringFor:nBytes