diff --git a/src/UsefulBuf.c b/src/UsefulBuf.c
index f5149a5..1a6b385 100644
--- a/src/UsefulBuf.c
+++ b/src/UsefulBuf.c
@@ -254,22 +254,21 @@
    }
 
    /* 3. Slide existing data to the right */
-   uint8_t *pSourceOfMove       = ((uint8_t *)pMe->UB.ptr) + uInsertionPos; // PtrMath #1
-   size_t   uNumBytesToMove     = pMe->data_len - uInsertionPos; // PtrMath #2
-   uint8_t *pDestinationOfMove  = pSourceOfMove + NewData.len; // PtrMath #3
+   if (!UsefulOutBuf_IsBufferNULL(pMe)) {
+      uint8_t *pSourceOfMove       = ((uint8_t *)pMe->UB.ptr) + uInsertionPos; // PtrMath #1
+      size_t   uNumBytesToMove     = pMe->data_len - uInsertionPos; // PtrMath #2
+      uint8_t *pDestinationOfMove  = pSourceOfMove + NewData.len; // PtrMath #3
 
-   if(uNumBytesToMove && pMe->UB.ptr) {
       // To know memmove won't go off end of destination, see PtrMath #4
       // Use memove because it handles overlapping buffers
       memmove(pDestinationOfMove, pSourceOfMove, uNumBytesToMove);
-   }
 
-   /* 4. Put the new data in */
-   uint8_t *pInsertionPoint = ((uint8_t *)pMe->UB.ptr) + uInsertionPos; // PtrMath #5
-   if(pMe->UB.ptr) {
-      // To know memmove won't go off end of destination, see PtrMath #6
+      /* 4. Put the new data in */
+      uint8_t *pInsertionPoint = pSourceOfMove;
+      // To know memmove won't go off end of destination, see PtrMath #5
       memmove(pInsertionPoint, NewData.ptr, NewData.len);
    }
+
    pMe->data_len += NewData.len;
 }
 
@@ -295,9 +294,7 @@
     Check #3 allows Check #2 to be refactored as NewData.Len > (me->size - uInsertionPos)
     This algebraically rearranges to me->size > uInsertionPos + NewData.len
 
- PtrMath #5 is exactly the same as PtrMath #1
-
- PtrMath #6 will never wrap under because
+ PtrMath #5 will never wrap under because
     Calculation for extent of memove is uRoomInDestination = me->UB.len - uInsertionPos;
     Check #1 makes sure me->data_len is less than me->size
     Check #3 makes sure uInsertionPos is less than me->data_len