Index: firmware/App/Modes/ModeFill.c
===================================================================
diff -u -r0c296cef29037819be204c45a23d4d38a52b2718 -re7aa2915e4a36b3622f0f75ed7ecd48796fc8649
--- firmware/App/Modes/ModeFill.c	(.../ModeFill.c)	(revision 0c296cef29037819be204c45a23d4d38a52b2718)
+++ firmware/App/Modes/ModeFill.c	(.../ModeFill.c)	(revision e7aa2915e4a36b3622f0f75ed7ecd48796fc8649)
@@ -71,6 +71,8 @@
 #define RO_PUMP_LOOKUP_TABLE_SIZE                       4                                                    ///< Size of array used as RO pump speed lookup table.
 #define CONCENTRATE_PUMP_PRIME_EXTRA_SPEED_ML_MIN       5.0F                                                 ///< Concentrate pump additional speed during priming in mL/min.
 #define CONCENTRATE_TEST_TIME_OUT_MS                    ( 30 * MS_PER_SECOND )                               ///< Concentrate test time out period in ms.
+#define DELAY_FMP_CHECK_START_BY_MS                     ( 10 * MS_PER_SECOND )                               ///< Delay start of FMP check during dialysate deliver state by this amount of time (in ms).
+
 // 2m long tubing to cap = 19.5 mL (acid line) + 7.92 mL/m * 2 m (tubing to cap) + 20.82 mL (straw) = 56.15 mL
 // Prime time in seconds = ( 56.15 mL / 48 mL/min ) x 60 second/min + 25 seconds margin time = 95 seconds.
 #define PRIME_CONCENTRATE_LINES_TIME_OUT_MS             ( 95 * MS_PER_SECOND )                               ///< Time required to prime the concentrate lines.
@@ -114,6 +116,7 @@
 static U32 concentratePumpPrimeCount;                                                                        ///< Interval count for concentrate pump prime.
 
 static F32 integratedVolumeML;                                                                               ///< Total RO flow rate over period of time.
+static BOOL didFMPCheckStart;                                                                                ///< Flag indicates whether FMP flow vs. LC volume check has begun.
 static F32 acidConductivityTotal;                                                                            ///< Total of acid conductivity during fill.
 static F32 bicarbConductivityTotal;                                                                          ///< Total of bicarb conductivity during fill.
 static U32 conductivitySampleCount;                                                                          ///< Sample count of conductivity during fill.
@@ -170,6 +173,7 @@
     dataPublishCounter            = DATA_PUBLISH_COUNTER_START_COUNT;
     reservoirBaseWeight           = 0.0F;
     integratedVolumeML            = 0.0F;
+    didFMPCheckStart              = FALSE;
     concentrateTestStartTime      = 0;
     acidConductivityTotal         = 0.0F;
     bicarbConductivityTotal       = 0.0F;
@@ -707,8 +711,8 @@
     {
         setValveState( VPO, VALVE_STATE_FILL_C_TO_NC );
 
-        reservoirBaseWeight        = getReservoirWeight( getInactiveReservoir() );
         dialysateFillStartTime     = getMSTimerCount();
+
         fillStatus.isThisFirstFill = FALSE;
         result                     = DG_FILL_MODE_STATE_DELIVER_DIALYSATE;
     }
@@ -744,7 +748,17 @@
     // Set concentrate pumps speed based on the RO pump flow rate
     handleDialysateMixing( getMeasuredFlowRateLPM( RO_FLOW_SENSOR ) * ML_PER_LITER, acidMix, bicarbMix );
 
-    integratedVolumeML      += getMeasuredROFlowRateWithConcPumpsLPM() * ML_PER_LITER * FLOW_INTEGRATOR;
+    // Delay start of FMP check, then begin integrating flow to a volume
+    if ( TRUE == didTimeout( dialysateFillStartTime, DELAY_FMP_CHECK_START_BY_MS ) )
+    {
+        if ( FALSE == didFMPCheckStart )
+        {   // When FMP check starts, set baseline weight of reservoir we are filling
+            didFMPCheckStart = TRUE;
+            reservoirBaseWeight        = getReservoirWeight( getInactiveReservoir() );
+        }
+        integratedVolumeML      += getMeasuredROFlowRateWithConcPumpsLPM() * ML_PER_LITER * FLOW_INTEGRATOR;
+    }
+
     usedAcidVolumeML.data   += getMeasuredPumpSpeed( CONCENTRATEPUMPS_CP1_ACID ) * FLOW_INTEGRATOR;
     usedBicarbVolumeML.data += getMeasuredPumpSpeed( CONCENTRATEPUMPS_CP2_BICARB ) * FLOW_INTEGRATOR;
     acidConductivityTotal   += acidConductivity;