Index: trunk/ppMerge/src/ppMergeMask.c
===================================================================
--- trunk/ppMerge/src/ppMergeMask.c	(revision 15653)
+++ trunk/ppMerge/src/ppMergeMask.c	(revision 15663)
@@ -113,4 +113,22 @@
             roOut->data_exists = cellOut->data_exists = chipOut->data_exists = true;
 
+            // Get list of cells for concepts averaging
+            {
+                psList *inCells = psListAlloc(NULL); // List of cells
+                for (int i = 0; i < filenames->n; i++) {
+                    if (! filenames->data[i] || strlen(filenames->data[i]) == 0) {
+                        continue;
+                    }
+                    pmCell *cellIn = pmFPAviewThisCell(view, data->in->data[i]); // Input cell
+                    psListAdd(inCells, PS_LIST_TAIL, cellIn);
+                }
+                if (!pmConceptsAverageCells(cellOut, inCells, NULL, NULL, true)) {
+                    psError(PS_ERR_UNKNOWN, false, "Unable to average cell concepts.");
+                    psFree(inCells);
+                    return false;
+                }
+                psFree(inCells);
+            }
+
             // Statistics on the merged cell
             if (data->statsFile) {
@@ -148,4 +166,23 @@
     }
 
+    // Get list of FPAs for concepts averaging
+    {
+        psList *inFPAs = psListAlloc(NULL); // List of FPAs
+        for (int i = 0; i < filenames->n; i++) {
+            if (! filenames->data[i] || strlen(filenames->data[i]) == 0) {
+                continue;
+            }
+            pmFPA *fpaIn = data->in->data[i]; // Input FPA
+            psListAdd(inFPAs, PS_LIST_TAIL, fpaIn);
+        }
+
+        if (!pmConceptsAverageFPAs(fpaOut, inFPAs)) {
+            psError(PS_ERR_UNKNOWN, false, "Unable to average FPA concepts.");
+            psFree(inFPAs);
+            return false;
+        }
+        psFree(inFPAs);
+    }
+
     if (fpaOut->hdu && !fpaOut->hdu->blankPHU) {
         psTrace("ppMerge", 5, "Writing out FPA HDU.\n");