diff --git a/src/lib/time/control.hpp b/src/lib/time/control.hpp
index 2a813aff6..398d2c172 100644
--- a/src/lib/time/control.hpp
+++ b/src/lib/time/control.hpp
@@ -162,7 +162,7 @@ namespace time {
     TI
     Mutator<TI>::imposeNudge (TimeValue& target, int off_by_steps)
     {
-      return TI (Mutation::imposeChange (target, TimeVar(target)+Time(FSecs(off_by_steps))));
+      return TI (Mutation::imposeChange (target, TimeVar(target)+Time(FSecs(off_by_steps))));     //////////////////TICKET #810
     }
     
     // special cases...
@@ -226,19 +226,19 @@ namespace time {
     }
     template<>
     QuTime
-    Mutator<QuTime>::imposeOffset (TimeValue&, Offset const&)
+    Mutator<QuTime>::imposeOffset (TimeValue& target, Offset const& off)
     {
-      throw error::Logic ("can't deliver result of the change as grid-aligned time, "
-                          "because it's not evident which concrete grid to use"
-                         ,LUMIERA_ERROR_UNKNOWN_GRID);                        //////////////////TODO: we could pick up a "default grid" from session?
+      return QuTime (Mutation::imposeChange (target, TimeVar(target)+off)
+                    ,getDefaultGridFallback()                                                     //////////////////TICKET #810
+                    );
     }
     template<>
     QuTime
-    Mutator<QuTime>::imposeNudge (TimeValue&, int)
+    Mutator<QuTime>::imposeNudge (TimeValue& target, int off_by_steps)
     {
-      throw error::Logic ("can't deliver result of the change as grid-aligned time, "
-                          "because it's not evident which concrete grid to use"
-                         ,LUMIERA_ERROR_UNKNOWN_GRID);
+      return QuTime (Mutation::imposeChange (target, TimeVar(target)+Time(FSecs(off_by_steps)))
+                    ,getDefaultGridFallback()                                                     //////////////////TICKET #810
+                    );
     }
 #endif //(End)quantisation special case    
     
diff --git a/src/lib/time/quantiser.cpp b/src/lib/time/quantiser.cpp
index fcb916004..61103008c 100644
--- a/src/lib/time/quantiser.cpp
+++ b/src/lib/time/quantiser.cpp
@@ -51,10 +51,19 @@ namespace time {
                            , LUMIERA_ERROR_UNKNOWN_GRID);
       return grid_found;
     }
-    
   }//(End) implementation helpers
   
   
+  PQuant
+  getDefaultGridFallback()
+  {
+    static PQuant globalDefaultGrid (new FixedFrameQuantiser(1));
+    return globalDefaultGrid;                                                    ///////////////////////TICKET #810
+  };
+  
+  
+  
+  
   
   Grid::~Grid() { } // hint to emit the VTable here...
   
diff --git a/src/lib/time/quantiser.hpp b/src/lib/time/quantiser.hpp
index 06df4d3f1..d7717bb03 100644
--- a/src/lib/time/quantiser.hpp
+++ b/src/lib/time/quantiser.hpp
@@ -64,6 +64,17 @@ namespace time {
   }
   
   
+  
+  /** @todo placeholder for accessing
+   *        a current or default session grid.
+   *        To be implemented later.
+   */
+  PQuant getDefaultGridFallback();                                        ///////////////////////TICKET #810
+  
+  
+  
+  
+  
   /**
    * Facility to create grid-aligned time values.
    * Effectively, a quantiser exposes the value Grid API, but
diff --git a/tests/lib/time/time-control-test.cpp b/tests/lib/time/time-control-test.cpp
index e85fc1685..1b5cb2dd7 100644
--- a/tests/lib/time/time-control-test.cpp
+++ b/tests/lib/time/time-control-test.cpp
@@ -297,7 +297,7 @@ namespace test{
       : BASE
       {
         void
-        performTestCases(TimeValue const& o, TimeValue const& c)
+        performTestCases(TimeValue const& org, TimeValue const& c)
           {
             cout << "Test-Case. Target=" << showType<TAR>() 
                  <<" <--feed--- "        << showType<SRC>() 
@@ -305,16 +305,16 @@ namespace test{
             
             Control<SRC> controller;
             
-            TAR target = TestTarget<TAR>::build(o);
+            TAR target = TestTarget<TAR>::build(org);
             target.accept (controller);
             
             SRC change = TestChange<SRC>::prepareChangeValue(c);
             controller (change);
-            verify_wasChanged (target, o, change);
+            verify_wasChanged (target, org, change);
             
             Offset offset(c);
             controller (offset);
-            verify_wasOffset (target, o, offset);
+            verify_wasOffset (target, org, offset);
             
             TAR oldState(target);
             controller (0);
@@ -337,7 +337,7 @@ namespace test{
             
             
             // tail recursion: further test combinations....
-            BASE::performTestCases(o,c);
+            BASE::performTestCases(org,c);
           }
       };