diff --git a/doc/plan.org b/doc/plan.org
index aadbbb8..a3f9099 100644
--- a/doc/plan.org
+++ b/doc/plan.org
@@ -5674,6 +5674,9 @@ Result: no reply, but translated packets seen on h3; wrong IPv4
 checksum; tcp checksum is ok
 -> doing manual calculation to see where diff comes from
 *** TODO Shifting / compile errors
+
+v1: wrong parenthesis
+
 #+BEGIN_CENTER
 p4c --target bmv2 --arch v1model --std p4-16 "../p4src/checksum_diff.p4" -o "/home/p4/master-thesis/p4src"
 ../p4src/actions_delta_checksum.p4(135): warning: <<: Shifting 16-bit value with 17
@@ -5688,6 +5691,26 @@ p4c --target bmv2 --arch v1model --std p4-16 "../p4src/checksum_diff.p4" -o "/ho
 Compilation Error
 
 #+END_CENTER
+
+v2: wrong bit width
+
+#+BEGIN_CENTER
+p4c --target bmv2 --arch v1model --std p4-16 "../p4src/checksum_diff.p4" -o "/home/p4/master-thesis/p4src"
+../p4src/actions_delta_checksum.p4(135): warning: <<: shifting value with 4 bits by 12
+    shift_tmp = (bit<16>) (hdr.ipv4.version << 12) +
+                           ^^^^^^^^^^^^^^^^^^^^^^
+../p4src/actions_delta_checksum.p4(136): warning: <<: shifting value with 4 bits by 8
+                (bit<16>) (hdr.ipv4.ihl << 8) +
+                           ^^^^^^^^^^^^^^^^^
+../p4src/actions_delta_checksum.p4(135): warning: <<: shifting value with 4 bits by 12
+    shift_tmp = (bit<16>) (hdr.ipv4.version << 12) +
+                           ^^^^^^^^^^^^^^^^^^^^^^
+../p4src/actions_delta_checksum.p4(136): warning: <<: shifting value with 4 bits by 8
+                (bit<16>) (hdr.ipv4.ihl << 8) +
+                           ^^^^^^^^^^^^^^^^^
+
+#+END_CENTER
+
 ** The NetPFGA saga
 Problems encountered:
 - The logfile for a compile run is 10k+ lines
diff --git a/p4src/actions_delta_checksum.p4 b/p4src/actions_delta_checksum.p4
index 37d8bf9..999ff8f 100644
--- a/p4src/actions_delta_checksum.p4
+++ b/p4src/actions_delta_checksum.p4
@@ -132,9 +132,9 @@ action delta_ipv4_from_v6_to_v4()
 
     Does NOT contain payload! -> can be done manually */
 
-    shift_tmp = (bit<16>) (hdr.ipv4.version   << 12) +
-                (bit<16>) (hdr.ipv4.ihl       << 8)  +
-                (bit<16>) (hdr.ipv4.diff_serv << 2)  +
+    shift_tmp = ((bit<16>) hdr.ipv4.version)   << 12) +
+                ((bit<16>) hdr.ipv4.ihl)       << 8)  +
+                ((bit<16>) hdr.ipv4.diff_serv) << 2)  +
                 ((bit<16>) hdr.ipv4.ecn);
     tmp = tmp + shift_tmp;