Index: firmware/App/Controllers/DialInFlow.c
===================================================================
diff -u -r5e77f78c5dee9dfb441bd5d2053f7f4ac50dc619 -r29e57b5232f605a871c62580e16a7db297aae992
--- firmware/App/Controllers/DialInFlow.c	(.../DialInFlow.c)	(revision 5e77f78c5dee9dfb441bd5d2053f7f4ac50dc619)
+++ firmware/App/Controllers/DialInFlow.c	(.../DialInFlow.c)	(revision 29e57b5232f605a871c62580e16a7db297aae992)
@@ -52,8 +52,10 @@
 
 #define DIP_HOME_RATE                        100             ///< target pump speed (in estimate mL/min) for homing.
 #define DIP_HOME_TIMEOUT_MS                  10000           ///< maximum time allowed for homing to complete (in ms).
-#define DIP_SPEED_CALC_INTERVAL              ( 40 / TASK_PRIORITY_INTERVAL )  ///< interval (ms/task time) at which the dialysate inlet pump speed is calculated.
-#define DIP_SPEED_CALC_BUFFER__LEN           25              ///< number of hall sensor counts kept in buffer to hold last 1 second of count data.
+/// interval (ms/task time) at which the blood pump speed is calculated (every 40 ms).
+#define DIP_SPEED_CALC_INTERVAL              ( 40 / TASK_PRIORITY_INTERVAL )
+/// number of hall sensor counts kept in buffer to hold last 1 second of count data.
+#define DIP_SPEED_CALC_BUFFER__LEN           ( 1000 / DIP_SPEED_CALC_INTERVAL / TASK_PRIORITY_INTERVAL )
 #define DIP_HALL_EDGE_COUNTS_PER_REV         48              ///< number of hall sensor edge counts per motor revolution.
 
 #define DIP_MAX_FLOW_VS_SPEED_DIFF_ML_MIN    50.0            ///< maximum difference between measured flow and flow implied by measured motor speed.
@@ -884,7 +886,9 @@
     {
         U16 dipMotorHallSensorCount = getFPGADialInPumpHallSensorCount();
         U32 nextIdx = INC_WRAP( dipMotorSpeedCalcIdx, 0, DIP_SPEED_CALC_BUFFER__LEN - 1 );
-        U16 incDelta = ( dipMotorHallSensorCount >= dipLastMotorHallSensorCounts[ nextIdx ] ? dipMotorHallSensorCount - dipLastMotorHallSensorCounts[ nextIdx ] : ( HEX_64_K - dipLastMotorHallSensorCounts[ nextIdx ] ) + dipMotorHallSensorCount );
+        U16 incDelta = ( dipMotorHallSensorCount >= dipLastMotorHallSensorCounts[ dipMotorSpeedCalcIdx ] ? \
+                         dipMotorHallSensorCount - dipLastMotorHallSensorCounts[ dipMotorSpeedCalcIdx ] : \
+                         ( HEX_64_K - dipLastMotorHallSensorCounts[ dipMotorSpeedCalcIdx ] ) + dipMotorHallSensorCount );
         U16 decDelta = HEX_64_K - incDelta;
         U16 delta;