Tidied up M307 processing

src/Heating/Heater.cpp

@@ -151,22 +151,18 @@ GCodeResult Heater::SetOrReportModel(unsigned int heater, GCodeBuffer& gb, const
 
 	if (gb.Seen('K'))
 	{
-		// New style model parameters
+		// New style cooling rate parameters
 		seen = true;
 		float coolingRates[2];
 		size_t numValues = 2;
 		gb.GetFloatArray(coolingRates, numValues, false);
 		basicCoolingRate = coolingRates[0];
 		fanCoolingRate = (numValues == 2) ? coolingRates[1] : 0.0;
-		if (gb.Seen('R'))
-		{
-			heatingRate = gb.GetPositiveFValue();
-		}
 		gb.TryGetFValue('E', coolingRateExponent, seen);
 	}
 	else if (gb.Seen('C'))
 	{
-		// Old style model parameters
+		// Old style cooling time constant parameters
 		seen = true;
 		float timeConstants[2];
 		size_t numValues = 2;
@@ -176,17 +172,17 @@ GCodeResult Heater::SetOrReportModel(unsigned int heater, GCodeBuffer& gb, const
 		coolingRateExponent = 1.0;
 	}
 
-	if (gb.TryGetFValue('R', heatingRate, seen))
+	if (gb.Seen('R'))
 	{
-		// We have the heating rate
+		seen = true;
+		heatingRate = gb.GetPositiveFValue();
 	}
 	else
 	{
 		float gain;
 		if (gb.TryGetFValue('A', gain, seen))
 		{
 			// Old style heating model. A = gain, C = cooling time constant
-			seen = true;
 			heatingRate = gain * basicCoolingRate * 0.01;
 		}
 	}