diff --git a/src/hb-aat-layout-common.hh b/src/hb-aat-layout-common.hh
index a8c4b7637..e4851ce08 100644
--- a/src/hb-aat-layout-common.hh
+++ b/src/hb-aat-layout-common.hh
@@ -678,7 +678,7 @@ struct ObsoleteTypes
 				     const void *base,
 				     const T *array)
   {
-    return (offset - ((const char *) array - (const char *) base)) / sizeof (T);
+    return (offset - ((const char *) array - (const char *) base)) / T::static_size;
   }
   template <typename T>
   static unsigned int byteOffsetToIndex (unsigned int offset,
diff --git a/src/hb-aat-layout-kerx-table.hh b/src/hb-aat-layout-kerx-table.hh
index 25de8c6c0..c1d8815ae 100644
--- a/src/hb-aat-layout-kerx-table.hh
+++ b/src/hb-aat-layout-kerx-table.hh
@@ -392,7 +392,7 @@ struct KerxSubTableFormat2
 
     const UnsizedArrayOf<FWORD> &arrayZ = this+array;
     unsigned int kern_idx = l + r;
-    kern_idx = Types::offsetToIndex (kern_idx, this, &arrayZ);
+    kern_idx = Types::offsetToIndex (kern_idx, this, arrayZ.arrayZ);
     const FWORD *v = &arrayZ[kern_idx];
     if (unlikely (!v->sanitize (&c->sanitizer))) return 0;