diff --git a/src/truetype/ttinterp.c b/src/truetype/ttinterp.c
index 44400fbe2..2ea09db1e 100644
--- a/src/truetype/ttinterp.c
+++ b/src/truetype/ttinterp.c
@@ -4924,7 +4924,7 @@
                               FT_F26Dot6*     x,
                               FT_F26Dot6*     y,
                               TT_GlyphZone    zone,
-                              FT_UShort*      refp )
+                              FT_UInt*        refp )
   {
     TT_GlyphZoneRec  zp;
     FT_UShort        p;
@@ -4965,10 +4965,9 @@
   /* See `ttinterp.h' for details on backward compatibility mode. */
   static void
   Move_Zp2_Point( TT_ExecContext  exc,
-                  FT_UShort       point,
+                  FT_UInt         point,
                   FT_F26Dot6      dx,
-                  FT_F26Dot6      dy,
-                  FT_Bool         touch )
+                  FT_F26Dot6      dy )
   {
     if ( exc->GS.freeVector.x != 0 )
     {
@@ -4978,8 +4977,7 @@
 #endif
         exc->zp2.cur[point].x = ADD_LONG( exc->zp2.cur[point].x, dx );
 
-      if ( touch )
-        exc->zp2.tags[point] |= FT_CURVE_TAG_TOUCH_X;
+      exc->zp2.tags[point] |= FT_CURVE_TAG_TOUCH_X;
     }
 
     if ( exc->GS.freeVector.y != 0 )
@@ -4990,8 +4988,7 @@
 #endif
         exc->zp2.cur[point].y = ADD_LONG( exc->zp2.cur[point].y, dy );
 
-      if ( touch )
-        exc->zp2.tags[point] |= FT_CURVE_TAG_TOUCH_Y;
+      exc->zp2.tags[point] |= FT_CURVE_TAG_TOUCH_Y;
     }
   }
 
@@ -5008,10 +5005,10 @@
   {
     FT_Long          loop = exc->GS.loop;
     TT_GlyphZoneRec  zp;
-    FT_UShort        refp;
+    FT_UInt          refp;
 
     FT_F26Dot6       dx, dy;
-    FT_UShort        point;
+    FT_UInt          point;
 
 
     if ( exc->new_top < loop )
@@ -5028,7 +5025,7 @@
 
     while ( loop-- )
     {
-      point = (FT_UShort)*(--args);
+      point = (FT_UInt)*(--args);
 
       if ( BOUNDS( point, exc->zp2.n_points ) )
       {
@@ -5039,7 +5036,7 @@
         }
       }
       else
-        Move_Zp2_Point( exc, point, dx, dy, TRUE );
+        Move_Zp2_Point( exc, point, dx, dy );
     }
 
   Fail:
@@ -5062,11 +5059,10 @@
            FT_Long*        args )
   {
     TT_GlyphZoneRec  zp;
-    FT_UShort        refp;
+    FT_UInt          refp, start, limit, i;
     FT_F26Dot6       dx, dy;
 
     FT_UShort        contour, bounds;
-    FT_UShort        start, limit, i;
 
 
     contour = (FT_UShort)args[0];
@@ -5082,6 +5078,9 @@
     if ( Compute_Point_Displacement( exc, &dx, &dy, &zp, &refp ) )
       return;
 
+    if ( zp.cur != exc->zp2.cur )
+      refp = ~0U;  /* nan */
+
     if ( contour == 0 )
       start = 0;
     else
@@ -5095,8 +5094,8 @@
 
     for ( i = start; i < limit; i++ )
     {
-      if ( zp.cur != exc->zp2.cur || refp != i )
-        Move_Zp2_Point( exc, i, dx, dy, TRUE );
+      if ( refp != i )
+        Move_Zp2_Point( exc, i, dx, dy );
     }
   }
 
@@ -5111,16 +5110,27 @@
   Ins_SHZ( TT_ExecContext  exc,
            FT_Long*        args )
   {
+    FT_Vector*       cur;
     TT_GlyphZoneRec  zp;
-    FT_UShort        refp;
-    FT_F26Dot6       dx,
-                     dy;
-
-    FT_UShort        limit, i;
+    FT_UInt          refp, i, limit;
+    FT_F26Dot6       dx, dy;
 
 
-    if ( BOUNDS( args[0], 2 ) )
+    /* XXX: UNDOCUMENTED! SHZ doesn't move the phantom points, */
+    /*      which must be subtracted.                          */
+    switch ( (FT_Int)args[0] )
     {
+    case 0:
+      cur   = exc->twilight.cur;
+      limit = exc->twilight.n_points;
+      break;
+
+    case 1:
+      cur   = exc->pts.cur;
+      limit = exc->pts.n_points > 4U ? exc->pts.n_points - 4U : 0;
+      break;
+
+    default:
       if ( exc->pedantic_hinting )
         exc->error = FT_THROW( Invalid_Reference );
       return;
@@ -5129,22 +5139,34 @@
     if ( Compute_Point_Displacement( exc, &dx, &dy, &zp, &refp ) )
       return;
 
-    /* XXX: UNDOCUMENTED! SHZ doesn't move the phantom points.     */
-    /*      Twilight zone has no real contours, so use `n_points'. */
-    /*      Normal zone's `n_points' includes phantoms, so must    */
-    /*      subtract them.                                         */
-    if ( exc->GS.gep2 == 0 )
-      limit = exc->zp2.n_points;
-    else if ( exc->zp2.n_points > 4U )
-      limit = exc->zp2.n_points - 4U;
-    else
-      return;
+    if ( zp.cur != cur )
+      refp = ~0U;  /* nan */
 
-    /* XXX: UNDOCUMENTED! SHZ doesn't touch the points */
-    for ( i = 0; i < limit; i++ )
+    /* XXX: UNDOCUMENTED! SHZ doesn't touch the points. */
+    if ( dx )
     {
-      if ( zp.cur != exc->zp2.cur || refp != i )
-        Move_Zp2_Point( exc, i, dx, dy, FALSE );
+#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
+      /* See `ttinterp.h' for details on backward compatibility mode. */
+      if ( !exc->backward_compatibility )
+#endif
+        for ( i = 0; i < limit; i++ )
+        {
+          if ( refp != i )
+            cur[i].x = ADD_LONG( cur[i].x, dx );
+        }
+    }
+
+    if ( dy )
+    {
+#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
+      /* See `ttinterp.h' for details on backward compatibility mode. */
+      if ( exc->backward_compatibility != 0x7 )
+#endif
+        for ( i = 0; i < limit; i++ )
+        {
+          if ( refp != i )
+            cur[i].y = ADD_LONG( cur[i].y, dy );
+        }
     }
   }
 
@@ -5161,7 +5183,7 @@
   {
     FT_Long     loop = exc->GS.loop;
     FT_F26Dot6  dx, dy;
-    FT_UShort   point;
+    FT_UInt     point;
 #ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
     FT_Bool     in_twilight = FT_BOOL( exc->GS.gep0 == 0 ||
                                        exc->GS.gep1 == 0 ||
@@ -5183,7 +5205,7 @@
 
     while ( loop-- )
     {
-      point = (FT_UShort)*(--args);
+      point = (FT_UInt)*(--args);
 
       if ( BOUNDS( point, exc->zp2.n_points ) )
       {
@@ -5206,11 +5228,11 @@
              ( exc->backward_compatibility != 0x7                     &&
                ( ( exc->is_composite && exc->GS.freeVector.y != 0 ) ||
                  ( exc->zp2.tags[point] & FT_CURVE_TAG_TOUCH_Y )    ) ) )
-          Move_Zp2_Point( exc, point, 0, dy, TRUE );
+          Move_Zp2_Point( exc, point, 0, dy );
       }
       else
 #endif
-        Move_Zp2_Point( exc, point, dx, dy, TRUE );
+        Move_Zp2_Point( exc, point, dx, dy );
     }
 
   Fail: