diff --git a/config/gen/config_h/config_h.in b/config/gen/config_h/config_h.in
index cb52980466..b35f944d2d 100644
--- a/config/gen/config_h/config_h.in
+++ b/config/gen/config_h/config_h.in
@@ -96,6 +96,7 @@ typedef @float8_t@                  Parrot_Float8;
  */
 #ifndef PARROT_GC_DEFAULT_TYPE
 #  define PARROT_GC_DEFAULT_TYPE @gc_type@
+#  define PARROT_GC_DEFAULT_@gc_type@
 #endif
 
 #if defined(PARROT_IN_CORE)
diff --git a/src/gc/gc_ms.c b/src/gc/gc_ms.c
index 636e872cbf..e47b01209c 100644
--- a/src/gc/gc_ms.c
+++ b/src/gc/gc_ms.c
@@ -1204,9 +1204,7 @@ Parrot_gc_create_attrib_pool(size_t attrib_idx)
     newpool->attr_size         = attrib_size;
     newpool->total_objects     = 0;
     newpool->objects_per_alloc = num_objs;
-#ifdef GC_STATS
     newpool->num_free_objects  = 0;
-#endif
     newpool->free_list         = NULL;
     newpool->top_arena         = NULL;
 
@@ -1665,7 +1663,9 @@ gc_ms_get_free_object(PARROT_INTERP,
         goto HAVE_FREE;
     }
 
+#ifdef GC_STATS
     --pool->num_free_objects;
+#endif
     interp->gc_sys->stats.memory_used += pool->object_size;
 
     return ptr;
diff --git a/src/gc/gc_private.h b/src/gc/gc_private.h
index bcb309b64a..f1c80a0b9d 100644
--- a/src/gc/gc_private.h
+++ b/src/gc/gc_private.h
@@ -25,14 +25,12 @@ Parrot.
 #include "parrot/settings.h"
 #include "variable_size_pool.h"
 
-/* Do not calculate private gc statistics, only used in gc_ms.
-   Currently skipped: num_free_objects.
- */
+/* Do not calculate num_free_objects, only used in gc_ms. */
 #ifndef GC_STATS
-#  ifdef NDEBUG
-#    undef GC_STATS
-#  else
+#  if !defined(NDEBUG) || defined(PARROT_GC_DEFAULT_MS) || defined(PARROT_GC_DEFAULT_MS2)
 #    define GC_STATS
+#  else
+#    undef GC_STATS
 #  endif
 #endif
 
@@ -325,11 +323,9 @@ typedef struct PMC_Attribute_Arena {
 
 typedef struct PMC_Attribute_Pool {
     size_t attr_size;                    /* Size of attribute object. */
+    size_t num_free_objects;             /* Number of objects on the free list. */
     size_t total_objects;                /* Total objects in the pool. */
     size_t objects_per_alloc;            /* Number of object slots to allocate. */
-#ifdef GC_STATS
-    size_t num_free_objects;             /* Number of objects on the free list. */
-#endif
     PMC_Attribute_Free_List * free_list; /* List of free object slots, or NULL. */
     PMC_Attribute_Arena     * top_arena; /* Pointer to most recent arena. */
     PMC_Attribute_Free_List * newfree;   /* Pointer to next object slot in