Index: firmware/App/Modes/ModeTreatment.c
===================================================================
diff -u -rf861c4c5ab64f429e0b8b9cc456e2ed14e472f2b -ra60ec05d359c0d3f014015e9080b6dbcef0fea28
--- firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision f861c4c5ab64f429e0b8b9cc456e2ed14e472f2b)
+++ firmware/App/Modes/ModeTreatment.c	(.../ModeTreatment.c)	(revision a60ec05d359c0d3f014015e9080b6dbcef0fea28)
@@ -701,7 +701,9 @@
 /*********************************************************************//**
  * @brief
  * The broadcastTreatmentSettingsRanges function computes and broadcasts \n
- * updated treatment parameter ranges that the user may change during treatment.
+ * updated treatment parameter ranges that the user may change during treatment. \n
+ * It is assumed that prescription settings have already been set prior to calling \n
+ * this function.
  * @details
  * Inputs : current operating mode, treatment states and parameters
  * Outputs : valid ranges message sent on interval
@@ -712,21 +714,24 @@
     if ( ++treatmentParamsRangesBroadcastTimerCtr >= TREATMENT_SETTINGS_RANGES_PUB_INTERVAL )
     {
         // compute minimum treatment duration
-        U32 elapseTime = CALC_ELAPSED_TREAT_TIME_IN_MIN() + 2;        // add two minutes to cover rounding and ensure it's valid for next minute
-        U32 minTime = MAX( elapseTime, MIN_TREATMENT_TIME_MINUTES );  // treatment duration cannot be < 1 hour
+        U32 presTime = ( presTreatmentTimeSecs / SEC_PER_MIN );
+        U32 elapseTime = CALC_ELAPSED_TREAT_TIME_IN_MIN();
+        U32 minTime = MAX( (elapseTime + 2), MIN_TREATMENT_TIME_MINUTES );  // treatment duration cannot be < 1 hour. add two minutes to cover rounding and ensure it's valid for next minute
         // compute maximum treatment duration (from both UF and dialysate volume perspectives)
         U32 maxTimeRem = ( MAX_UF_VOLUME_ML - (U32)getUltrafiltrationVolumeCollected() ) / ( presUFRate > 0.0 ? (U32)presUFRate : 1 );
         U32 maxTime1 = minTime + maxTimeRem;
         U32 maxTime2 = MAX_DIALYSATE_VOLUME_ML / presDialysateFlowRate;
-        U32 maxTime = MIN( maxTime1, maxTime2 );
+        U32 maxTime = MAX( maxTime1, maxTime2 );
         // compute minimum UF volume
         F32 minUFVol = getUltrafiltrationVolumeCollected() + presUFRate;
-        // compute maximum UF volume (considering from adjustment of UF rate perspective)
-        F32 maxUFVol = ( presUFRate > 0.0 ? minUFVol + ( (F32)( MAX_TREATMENT_TIME_MINUTES - CALC_ELAPSED_TREAT_TIME_IN_MIN() - 1 ) * presUFRate ) : (F32)MAX_UF_VOLUME_ML );
+        // compute maximum UF volume (considering from adjustment of UF rate and time perspectives)
+        F32 maxUFVol1 = minUFVol + ( (F32)( presTime - elapseTime ) * MAX_UF_RATE_ML_MIN );
+        F32 maxUFVol2 = ( presUFRate > 0.0 ? minUFVol + ( (F32)( MAX_TREATMENT_TIME_MINUTES - elapseTime - 1 ) * presUFRate ) : minUFVol );
+        F32 maxUFVol = MAX( maxUFVol1, maxUFVol2 );
         // compute minimum dialysate flow rate
         U32 minDialRate = MIN_DIAL_IN_FLOW_RATE;
         // compute maximum dialysate flow rate from max dialysate volume perspective
-        U32 maxDialRate = MAX_DIALYSATE_VOLUME_ML / ( presTreatmentTimeSecs / SEC_PER_MIN );
+        U32 maxDialRate = MAX_DIALYSATE_VOLUME_ML / presTime;
 
         // now ensure maximums do not exceed the literal maximums
         maxTime = MIN( maxTime, MAX_TREATMENT_TIME_MINUTES );