diff --git a/src/lib/time/mutation.cpp b/src/lib/time/mutation.cpp
index e98bafb33..cd2b205c3 100644
--- a/src/lib/time/mutation.cpp
+++ b/src/lib/time/mutation.cpp
@@ -197,7 +197,7 @@ namespace time {
     public:
       explicit
       MaterialiseIntoTarget (QuTime const& quant)
-        : SetNewStartTimeMutation (Secs(quant).getTime())
+        : SetNewStartTimeMutation (PQuant(quant)->materialise(quant))
         { }
     };
   
@@ -264,8 +264,10 @@ namespace time {
       virtual void
       change (QuTime& target)   const
         {
-          long gridPoint = FrameNr(target)+steps_;
-          imposeChange (target, PQuant(target)->timeOf(gridPoint));
+          PQuant const& grid (target);
+          int64_t originalGridPoint = grid->gridPoint(target);
+          int64_t adjustedGridPoint = originalGridPoint + steps_;
+          imposeChange (target, grid->timeOf (adjustedGridPoint));
         }
       
    
diff --git a/src/lib/time/quantiser.cpp b/src/lib/time/quantiser.cpp
index 6ae061587..6a43b014a 100644
--- a/src/lib/time/quantiser.cpp
+++ b/src/lib/time/quantiser.cpp
@@ -47,7 +47,7 @@ namespace time {
       advice::Request<PQuant> query(gridID);
       PQuant grid_found = query.getAdvice();
       if (!grid_found)
-        throw error::Logic ("unable to fetch the quantisation grid -- is it already defined?"
+        throw error::Logic ("unable to fetch the quantisation grid -- was it already defined?"    ////////TICKET #197
                            , LUMIERA_ERROR_UNKNOWN_GRID);
       return grid_found;
     }
@@ -112,6 +112,27 @@ namespace time {
   }
   
   
+  
+  /** convenience shortcut: \em materialise a raw time value
+   *  based on this grid or time axis, but returning a raw time value. 
+   *  Implemented as combination of the #gridAlign and #timeOf operations,
+   *  i.e. we quantise into this scale, but transform the result back onto
+   *  the raw time value scale.
+   * @warning this operation incurs information loss. Values may be rounded
+   *          and / or clipped, according to the grid used. And, contrary to
+   *          a QuTime value, the information about the actual grid is
+   *          discarded. Please don't use this operation if you just
+   *          "want a number" but feel to too lazy to understand
+   *          properly what quantisation means!
+   */
+  TimeValue
+  Quantiser::materialise  (TimeValue const& raw)  const
+  {
+    return timeOf (gridPoint (raw));
+  }
+  
+  
+  
   /** alignment to a simple fixed size grid.
    *  The actual calculation first determines the number
    *  of the grid interval containing the given rawTime,
diff --git a/src/lib/time/quantiser.hpp b/src/lib/time/quantiser.hpp
index a8efad7a1..33c4e9d3f 100644
--- a/src/lib/time/quantiser.hpp
+++ b/src/lib/time/quantiser.hpp
@@ -93,6 +93,7 @@ namespace time {
         }
       
       static PQuant retrieve (Symbol gridID);
+      TimeValue materialise  (TimeValue const& raw)       const;
       
       
       //------Grid-API----------------------------------------------