diff --git a/qa/1131 b/qa/1131
index 118375d4252..026a6ebd972 100755
--- a/qa/1131
+++ b/qa/1131
@@ -31,6 +31,7 @@ signal=$PCP_BINADM_DIR/pmsignal
 trap "_cleanup; exit \$status" 0 1 2 3 15
 
 A="$here/archives/rep"
+A1="$here/archives/20180606"
 hostname=`hostname`
 machineid=`_machine_id`
 domainid=`_domain_name`
@@ -98,6 +99,8 @@ pcp2openmetrics -s1 -z hinv.ncpu | _filter_pcp2openmetrics
 echo "---"
 pcp2openmetrics -s2 -x hinv.ncpu | _filter_pcp2openmetrics
 echo "---"
+pcp2openmetrics -s2 -a $A1 hinv.ncpu disk.partitions.write | _archive_filter
+echo "---"
 pcp2opentelemetry -s1 -H -z hinv.ncpu | _filter_pcp2opentelemetry
 echo "---"
 
diff --git a/qa/1131.out b/qa/1131.out
index a8fde64d5b3..a6e98b01395 100644
--- a/qa/1131.out
+++ b/qa/1131.out
@@ -2279,6 +2279,18 @@ hinv_ncpu{domainname="DOMAINID",groupid="GROUPID",hostname="HOST",machineid="MAC
 hinv_ncpu{domainname="DOMAINID",groupid="GROUPID",hostname="HOST",machineid="MACHINEID",userid="USERID",agent="AGENT"} NCPU
 hinv_ncpu{domainname="DOMAINID",groupid="GROUPID",hostname="HOST",machineid="MACHINEID",userid="USERID",agent="AGENT"} NCPU
 ---
+# PCP5 hinv_ncpu 60.0.32 u32 PM_INDOM_NULL discrete 
+# TYPE hinv_ncpu gauge
+# HELP hinv_ncpu number of CPUs in the system
+hinv_ncpu{domainname="localdomain",groupid="999",hostname="vm01",machineid="3a6b3d7f3b7559c538a5934a24866658",userid="999",agent="linux"} 1 1528207821.599573
+# PCP5 disk_partitions_write 60.10.1 u32 60.10 counter count
+# TYPE disk_partitions_write counter
+# HELP disk_partitions_write write operations metric for storage partitions
+disk_partitions_write_total{domainname="localdomain",groupid="999",hostname="vm01",machineid="3a6b3d7f3b7559c538a5934a24866658",userid="999",instname="sda1",instid="1",agent="linux",device_type="block",indom_name="per partition"} 88156 1528207821.599573
+disk_partitions_write_total{domainname="localdomain",groupid="999",hostname="vm01",machineid="3a6b3d7f3b7559c538a5934a24866658",userid="999",instname="sda2",instid="2",agent="linux",device_type="block",indom_name="per partition"} 0 1528207821.599573
+disk_partitions_write_total{domainname="localdomain",groupid="999",hostname="vm01",machineid="3a6b3d7f3b7559c538a5934a24866658",userid="999",instname="sda5",instid="3",agent="linux",device_type="block",indom_name="per partition"} 2293 1528207821.599573
+# EOF
+---
 {
   "resourceMetrics": [
     {
diff --git a/src/pcp2openmetrics/pcp2openmetrics.py b/src/pcp2openmetrics/pcp2openmetrics.py
index a228aaf340c..bc935fab039 100755
--- a/src/pcp2openmetrics/pcp2openmetrics.py
+++ b/src/pcp2openmetrics/pcp2openmetrics.py
@@ -104,7 +104,7 @@ def __init__(self):
         self.precision = 3 # .3f
         self.precision_force = None
         self.timefmt = TIMEFMT
-        self.interpol = 0
+        self.interpol = 1
         self.count_scale = None
         self.count_scale_force = None
         self.space_scale = None
@@ -121,7 +121,7 @@ def __init__(self):
         self.http_pass = None
         self.http_timeout = TIMEOUT
         self.no_comment = False
-        self.header_flag = True
+        self.headers = []
 
         # Internal
         self.runtime = -1
@@ -476,12 +476,12 @@ def openmetrics_labels(inst, name, desc, labels):
             help_dict = {}
             help_dict[metric] = context.pmLookupText(pmid[0])
 
-            if self.header_flag is True:
+            if metric not in self.headers:
                 if self.no_comment is False:
                     body += '# PCP5 %s %s %s %s %s %s\n' % (openmetrics_name(metric), pmIDStr, get_type_string(desc), pmIndomStr, semantics, units)
                 body += '# TYPE %s %s\n' % (openmetrics_name(metric), openmetrics_type(desc))
                 body += '# HELP %s %s\n' % (openmetrics_name(metric), help_dict[metric])
-                self.header_flag = False
+                self.headers.append(metric)
 
             for inst, name, value in results[metric]:
                 if isinstance(value, float):