diff --git a/tests/grib_ecc-604-1.c b/tests/grib_ecc-604-1.c
index d50ec7958..2ba11d628 100644
--- a/tests/grib_ecc-604-1.c
+++ b/tests/grib_ecc-604-1.c
@@ -7,9 +7,10 @@
 
 #include "grib_api.h"
 
-static size_t NUM_THREADS         = 8;
-static size_t FILES_PER_ITERATION = 300;
-static char* INPUT_FILE           = NULL;
+/* These are passed in via argv */
+static size_t NUM_THREADS         = 0;
+static size_t FILES_PER_ITERATION = 0;
+static char*  INPUT_FILE          = NULL;
 
 static int encode_file(char *template_file, char *output_file)
 {
@@ -28,7 +29,8 @@ static int encode_file(char *template_file, char *output_file)
         int i;
         long count;
         double d,e;
-        size_t values_len= 0;
+        size_t values_len = 0;
+        size_t str_len = 20;
 
         grib_handle *clone_handle = grib_handle_clone(source_handle);
         assert(clone_handle);
@@ -44,10 +46,14 @@ static int encode_file(char *template_file, char *output_file)
             if (count>100) {e*=10; count=1;}
             values[i]=d;
             d+=e;
+            if (d > 10000) d = 0;
             count++;
         }
 
-        GRIB_CHECK(grib_set_long(clone_handle,"bitsPerValue",16),0);
+        GRIB_CHECK(grib_set_string(clone_handle,"stepUnits", "s", &str_len),0);
+        GRIB_CHECK(grib_set_long(clone_handle, "startStep", 43200), 0);
+        GRIB_CHECK(grib_set_long(clone_handle, "endStep", 86400), 0);
+        GRIB_CHECK(grib_set_long(clone_handle, "bitsPerValue", 16),0);
 
         /* set data values */
         GRIB_CHECK(grib_set_double_array(clone_handle,"values",values,values_len),0);
diff --git a/tests/grib_ecc-604-2.c b/tests/grib_ecc-604-2.c
index fc15d1206..183a6ca13 100644
--- a/tests/grib_ecc-604-2.c
+++ b/tests/grib_ecc-604-2.c
@@ -9,9 +9,10 @@
 
 #include "grib_api.h"
 
-static size_t NUM_THREADS         = 8;
-static size_t FILES_PER_ITERATION = 300;
-static char* INPUT_FILE           = NULL;
+/* These are passed in via argv */
+static size_t NUM_THREADS         = 0;
+static size_t FILES_PER_ITERATION = 0;
+static char*  INPUT_FILE          = NULL;
 
 static int encode_file(char *template_file, char *output_file)
 {
@@ -30,7 +31,8 @@ static int encode_file(char *template_file, char *output_file)
         int i;
         long count;
         double d,e;
-        size_t values_len= 0;
+        size_t values_len = 0;
+        size_t str_len = 20;
 
         /*GRIB_CHECK(grib_set_long(source_handle, "centre", 250),0);*/
         GRIB_CHECK(grib_get_size(source_handle, "values", &values_len),0);
@@ -43,10 +45,14 @@ static int encode_file(char *template_file, char *output_file)
             if (count>100) {e*=10; count=1;}
             values[i]=d;
             d+=e;
+            if (d > 10000) d = 0;
             count++;
         }
 
-        GRIB_CHECK(grib_set_long(source_handle,"bitsPerValue",16),0);
+        GRIB_CHECK(grib_set_string(source_handle,"stepUnits", "s", &str_len),0);
+        GRIB_CHECK(grib_set_long(source_handle, "startStep", 43200), 0);
+        GRIB_CHECK(grib_set_long(source_handle, "endStep", 86400), 0);
+        GRIB_CHECK(grib_set_long(source_handle, "bitsPerValue", 16),0);
 
         /* set data values */
         GRIB_CHECK(grib_set_double_array(source_handle,"values",values,values_len),0);
diff --git a/tests/grib_ecc-604-3.c b/tests/grib_ecc-604-3.c
index 84b1b5654..8e9c4075d 100644
--- a/tests/grib_ecc-604-3.c
+++ b/tests/grib_ecc-604-3.c
@@ -8,9 +8,10 @@
 
 #include "grib_api.h"
 
-static size_t NUM_THREADS         = 8;
-static size_t FILES_PER_ITERATION = 300;
-static char* INPUT_FILE           = NULL;
+/* These are passed in via argv */
+static size_t NUM_THREADS         = 0;
+static size_t FILES_PER_ITERATION = 0;
+static char*  INPUT_FILE          = NULL;
 
 static int decode_file(char *template_file)
 {
@@ -28,7 +29,8 @@ static int decode_file(char *template_file)
         int i;
         long count;
         double d,e;
-        size_t values_len= 0;
+        size_t values_len = 0;
+        size_t str_len = 20;
 
         grib_handle *clone_handle = grib_handle_clone(source_handle);
         assert(clone_handle);
@@ -44,10 +46,14 @@ static int decode_file(char *template_file)
             if (count>100) {e*=10; count=1;}
             values[i]=d;
             d+=e;
+            if (d > 10000) d = 0;
             count++;
         }
 
-        GRIB_CHECK(grib_set_long(clone_handle,"bitsPerValue",16),0);
+        GRIB_CHECK(grib_set_string(clone_handle,"stepUnits", "s", &str_len),0);
+        GRIB_CHECK(grib_set_long(clone_handle, "startStep", 43200), 0);
+        GRIB_CHECK(grib_set_long(clone_handle, "endStep", 86400), 0);
+        GRIB_CHECK(grib_set_long(clone_handle, "bitsPerValue", 16),0);
 
         /* set data values */
         GRIB_CHECK(grib_set_double_array(clone_handle,"values",values,values_len),0);
diff --git a/tests/grib_ecc-604.sh b/tests/grib_ecc-604.sh
index d3e39f1f3..6147c0217 100755
--- a/tests/grib_ecc-604.sh
+++ b/tests/grib_ecc-604.sh
@@ -16,22 +16,27 @@ temp_dir=tempdir.${label}
 validate()
 {
     echo "Checking every output file is identical..."
+    # Get checksum of first file
+    ck1=`cksum $OUTPUT/output_file_0-0.grib | awk '{print $1}'`
     set +x
+    # Get checksum of all of them and sort unique
     res=`cksum $OUTPUT/output_file_* | awk '{print $1}' | sort -u`
     set -x
-    [ "$res" = "2572910830" ]
+    # Should be the same as the first
+    [ "$res" = "$ck1" ]
 }
 
-NUM_THREADS=8
-NUM_ITER=300
+NUM_THREADS=6
+NUM_ITER=200
 OUTPUT=output
 input=$ECCODES_SAMPLES_PATH/gg_sfc_grib2.tmpl
+# input=$ECCODES_SAMPLES_PATH/gg_sfc_grib1.tmpl
 
 rm -fr $temp_dir
 mkdir -p $temp_dir
 cd $temp_dir
 
-# Test 01: clone + output
+# Test 01: Clone + output
 # ------------------------
 mkdir -p $OUTPUT
 time ${test_dir}/grib_ecc-604-1 par $input $NUM_THREADS $NUM_ITER
@@ -44,7 +49,7 @@ mkdir -p $OUTPUT
 time ${test_dir}/grib_ecc-604-2 par $input $NUM_THREADS $NUM_ITER
 validate
 
-# Test 03: clone + no output
+# Test 03: Clone + no output
 # ---------------------------
 rm -fr $OUTPUT
 time ${test_dir}/grib_ecc-604-3 par $input $NUM_THREADS $NUM_ITER