diff --git a/src/drivers/ncmpio/ncmpio_getput.m4 b/src/drivers/ncmpio/ncmpio_getput.m4
index ea94c2afd..98b943f67 100644
--- a/src/drivers/ncmpio/ncmpio_getput.m4
+++ b/src/drivers/ncmpio/ncmpio_getput.m4
@@ -117,8 +117,8 @@ put_varm(NC               *ncp,
 {
     void *xbuf=NULL;
     int mpireturn, err=NC_NOERR, status=NC_NOERR, buftype_is_contig;
-    int el_size, need_convert, need_swap, in_place_swap, need_swap_back_buf=0;
-    int coll_indep, xtype_is_contig=1;
+    int el_size, need_convert, need_swap, need_swap_back_buf=0;
+    int coll_indep, xtype_is_contig=1, can_swap_in_place;
     MPI_Offset nelems=0, bnelems=0, nbytes=0, offset=0;
     MPI_Datatype itype, xtype=MPI_BYTE, imaptype, filetype=MPI_BYTE;
     MPI_File fh;
@@ -168,13 +168,14 @@ put_varm(NC               *ncp,
     need_convert = ncmpii_need_convert(ncp->format, varp->xtype, itype);
     need_swap    = NEED_BYTE_SWAP(varp->xtype, itype);
 
-    in_place_swap = 0;
+    /* check if in-place byte swap can be enabled */
+    can_swap_in_place = 1;
     if (need_swap) {
-        if (fIsSet(ncp->flags, NC_MODE_SWAP_ON))
-            in_place_swap = 1;
-        else if (! fIsSet(ncp->flags, NC_MODE_SWAP_OFF)) { /* auto mode */
+        if (! fIsSet(ncp->flags, NC_MODE_SWAP_OFF)) /* hint set by user */
+            can_swap_in_place = 0;
+        else if (! fIsSet(ncp->flags, NC_MODE_SWAP_ON)) { /* auto mode */
             if (nbytes > NC_BYTE_SWAP_BUFFER_SIZE)
-                in_place_swap = 1;
+                can_swap_in_place = 0;
         }
     }
 
@@ -185,7 +186,7 @@ put_varm(NC               *ncp,
     if (err != NC_NOERR) goto err_check;
 
     if (!need_convert && imaptype == MPI_DATATYPE_NULL &&
-        (!need_swap || (in_place_swap && buftype_is_contig))) {
+        (!need_swap || (can_swap_in_place && buftype_is_contig))) {
         /* reuse buftype, bufcount, buf in later MPI file write */
         xbuf = buf;
         if (need_swap) {
diff --git a/src/drivers/ncmpio/ncmpio_i_getput.m4 b/src/drivers/ncmpio/ncmpio_i_getput.m4
index 09beb4add..2b0c4f02a 100644
--- a/src/drivers/ncmpio/ncmpio_i_getput.m4
+++ b/src/drivers/ncmpio/ncmpio_i_getput.m4
@@ -144,7 +144,7 @@ ncmpio_igetput_varm(NC               *ncp,
     void *xbuf=NULL;
     int i, err=NC_NOERR, abuf_index=-1, isize, xsize, new_nreqs, rem;
     int mpireturn, buftype_is_contig=1, need_convert, free_xbuf=0;
-    int need_swap, in_place_swap, need_swap_back_buf=0;
+    int need_swap, can_swap_in_place, need_swap_back_buf=0;
     MPI_Offset nelems=0, nbytes, *ptr;
     MPI_Datatype itype, xtype, imaptype;
     NC_lead_req *lead_req;
@@ -232,16 +232,15 @@ ncmpio_igetput_varm(NC               *ncp,
     need_convert = ncmpii_need_convert(ncp->format, varp->xtype, itype);
     need_swap    = NEED_BYTE_SWAP(varp->xtype, itype);
 
-    /* check if we can do byte swap in place */
-    if (fIsSet(ncp->flags, NC_MODE_SWAP_ON))
-        in_place_swap = 1;
-    else if (fIsSet(ncp->flags, NC_MODE_SWAP_OFF))
-        in_place_swap = 0;
-    else { /* mode is auto */
-        if (nbytes <= NC_BYTE_SWAP_BUFFER_SIZE)
-            in_place_swap = 0;
-        else
-            in_place_swap = 1;
+    /* check if in-place byte swap can be enabled */
+    can_swap_in_place = 1;
+    if (need_swap) {
+        if (! fIsSet(ncp->flags, NC_MODE_SWAP_OFF)) /* hint set by user */
+            can_swap_in_place = 0;
+        else if (! fIsSet(ncp->flags, NC_MODE_SWAP_ON)) { /* auto mode */
+            if (nbytes > NC_BYTE_SWAP_BUFFER_SIZE)
+                can_swap_in_place = 0;
+        }
     }
 
     /* check whether this is a true varm call, if yes, imaptype will be a
@@ -265,7 +264,7 @@ ncmpio_igetput_varm(NC               *ncp,
         }
         else {
             if (!buftype_is_contig || imaptype != MPI_DATATYPE_NULL ||
-                need_convert || (need_swap && in_place_swap == 0)) {
+                need_convert || (need_swap && can_swap_in_place == 0)) {
                 /* cannot use buf for I/O, must allocate xbuf */
                 xbuf = NCI_Malloc((size_t)nbytes);
                 free_xbuf = 1;
diff --git a/src/drivers/ncmpio/ncmpio_i_varn.m4 b/src/drivers/ncmpio/ncmpio_i_varn.m4
index 55e0f3d32..073b39cad 100644
--- a/src/drivers/ncmpio/ncmpio_i_varn.m4
+++ b/src/drivers/ncmpio/ncmpio_i_varn.m4
@@ -169,13 +169,13 @@ igetput_varn(NC                *ncp,
 
     if (fIsSet(reqMode, NC_REQ_WR)) {
         /* check if in-place byte swap can be enabled */
-        int in_place_swap = 0;
+        int can_swap_in_place = 1;
         if (need_swap) {
-            if (fIsSet(ncp->flags, NC_MODE_SWAP_ON))
-                in_place_swap = 1;
-            else if (! fIsSet(ncp->flags, NC_MODE_SWAP_OFF)) { /* auto mode */
+            if (! fIsSet(ncp->flags, NC_MODE_SWAP_OFF)) /* hint set by user */
+                can_swap_in_place = 0;
+            else if (! fIsSet(ncp->flags, NC_MODE_SWAP_ON)) { /* auto mode */
                 if (nbytes > NC_BYTE_SWAP_BUFFER_SIZE)
-                    in_place_swap = 1;
+                    can_swap_in_place = 0;
             }
         }
 
@@ -195,7 +195,7 @@ igetput_varn(NC                *ncp,
             err = ncmpio_abuf_malloc(ncp, nbytes, &xbuf, &abuf_index);
             if (err != NC_NOERR) goto fn_exit;
         }
-        else if (!need_convert && in_place_swap && isContig) {
+        else if (!need_convert && can_swap_in_place && isContig) {
             /* reuse buf and break it into multiple vara requests */
             xbuf = buf;
             if (need_swap) need_swap_back_buf = 1;
diff --git a/src/drivers/ncmpio/ncmpio_vard.c b/src/drivers/ncmpio/ncmpio_vard.c
index 5de162106..e65d63df8 100644
--- a/src/drivers/ncmpio/ncmpio_vard.c
+++ b/src/drivers/ncmpio/ncmpio_vard.c
@@ -194,17 +194,19 @@ getput_vard(NC               *ncp,
     need_swap    = NEED_BYTE_SWAP(varp->xtype, etype);
 
     if (fIsSet(reqMode, NC_REQ_WR)) {
-        int in_place_swap = 0;
+        /* check if in-place byte swap can be enabled */
+        int can_swap_in_place = 1;
         if (need_swap) {
-            if (fIsSet(ncp->flags, NC_MODE_SWAP_ON))
-                in_place_swap = 1;
-            else if (! fIsSet(ncp->flags, NC_MODE_SWAP_OFF)) { /* auto mode */
+            if (! fIsSet(ncp->flags, NC_MODE_SWAP_OFF)) /* hint set by user */
+                can_swap_in_place = 0;
+            else if (! fIsSet(ncp->flags, NC_MODE_SWAP_ON)) { /* auto mode */
                 if (filetype_size > NC_BYTE_SWAP_BUFFER_SIZE)
-                    in_place_swap = 1;
+                    can_swap_in_place = 0;
             }
         }
+
         if (!need_convert &&
-            (!need_swap || (in_place_swap && buftype_is_contig))) {
+            (!need_swap || (can_swap_in_place && buftype_is_contig))) {
             /* reuse buftype, bufcount, buf in later MPI file write */
             xbuf = buf;
             if (need_swap) {