Index: trunk/psphot/src/psphotApResid.c
===================================================================
--- trunk/psphot/src/psphotApResid.c	(revision 9516)
+++ trunk/psphot/src/psphotApResid.c	(revision 9526)
@@ -55,6 +55,6 @@
 	apResid->data.F64[Npsf] = source->apMag - source->psfMag;
 
-	xPos->data.F64[Npsf]    = model->params->data.F32[2];
-	yPos->data.F64[Npsf]    = model->params->data.F32[3];
+	xPos->data.F64[Npsf]    = model->params->data.F32[PM_PAR_XPOS];
+	yPos->data.F64[Npsf]    = model->params->data.F32[PM_PAR_YPOS];
 
 	flux->data.F64[Npsf]    = pow(10.0, -0.4*source->psfMag);
@@ -73,5 +73,5 @@
 	}
 
-	dMag->data.F64[Npsf] = model->dparams->data.F32[1] / model->params->data.F32[1];
+	dMag->data.F64[Npsf] = model->dparams->data.F32[PM_PAR_FLUX] / model->params->data.F32[PM_PAR_FLUX];
 
 	psVectorExtend (mask, 	 100, 1);
@@ -93,5 +93,5 @@
     }
 
-    // APTREND options : NONE SKYBIAS XY_LIN XY_QUAD SKY_XY_LIN FULL 
+    // APTREND options are defined by the if ... else if ... else if ... else block below
     char *ApTrendOption = psMetadataLookupPtr (&status, recipe, "APTREND");
     if (!status) ApTrendOption = DEFAULT_OPTION;