diff --git a/controllers/keda/hpa.go b/controllers/keda/hpa.go
index 56d4a3e8ee9..286a9ce0eaf 100644
--- a/controllers/keda/hpa.go
+++ b/controllers/keda/hpa.go
@@ -252,7 +252,6 @@ func (r *ScaledObjectReconciler) getScaledObjectMetricSpecs(ctx context.Context,
 
 	// if ComplexScalingLogic struct is not nil, expect Formula or ExternalCalculation
 	// to be non-empty. If target is > 0.0 create a compositeScaler structure
-	// TODO: rename structures to unified name
 	if !reflect.DeepEqual(scaledObject.Spec.Advanced.ComplexScalingLogic, kedav1alpha1.ComplexScalingLogic{}) {
 		validNumTarget, validMetricType, err := validateCompositeScalingLogic(scaledObject, scaledObjectMetricSpecs)
 		if err != nil {
@@ -362,21 +361,35 @@ func validateCompositeScalingLogic(so *kedav1alpha1.ScaledObject, specs []autosc
 		// TODO: possibly validate formula here otherwise combine the two ifs above
 	}
 
+	// if ExternalCalculation is given, target doesnt need to be specified but can depending
+	// on if the user wants to use custom composite scaler
+	// if len(csl.ExternalCalculations) > 0 {
+	// TODO: check if connection to the endpoints are valid?
+	// }
+
 	if csl.Target != "" {
 		// convert string to float
 		num, err = strconv.ParseFloat(csl.Target, 64)
 		if err != nil || num <= 0.0 {
-			return -1, autoscalingv2.MetricTargetType(""), fmt.Errorf("error converting target for complex logic (string->float): %s", err)
+			return -1, autoscalingv2.MetricTargetType(""), fmt.Errorf("error converting target for complex logic (string->float): %w", err)
 		}
 	}
 
+	// if both are empty OR both are given its an error
+	// if (csl.Formula == "" && len(csl.ComplexScalingLogic) == 0) ||
+	// (csl.Formula != "" && len(csl.ComplexScalingLogic) > 0) {
+	// err := fmt.Errorf("error exactly one of Formula or ExternalCalculator can be given")
+	// return -1, autoscalingv2.MetricTargetType(""), err
+	// }
+
 	// if target is given, complex custom scaler for metric collection will be
 	// passed to HPA config -> all types need to be the same
 	if csl.Target != "" {
 		// make sure all scalers have the same metricTargetType
-		metricType = specs[0].External.Target.Type
-		for _, metric := range specs {
-			if metric.External.Target.Type != metricType {
+		for i, metric := range specs {
+			if i == 0 {
+				metricType = metric.External.Target.Type
+			} else if metric.External.Target.Type != metricType {
 				err := fmt.Errorf("error metric target type not the same for composite scaler: %s & %s", metricType, metric.External.Target.Type)
 				return -1, metricType, err
 			}
diff --git a/pkg/externalscaling/client.go b/pkg/externalscaling/client.go
index a06249ec6f6..e83a10dc044 100644
--- a/pkg/externalscaling/client.go
+++ b/pkg/externalscaling/client.go
@@ -39,7 +39,7 @@ func NewGrpcClient(url string, logger logr.Logger) (*GrpcClient, error) {
 	}
 	conn, err := grpc.Dial(url, opts...)
 	if err != nil {
-		return nil, fmt.Errorf("error in grpc.Dial: %s", err)
+		return nil, fmt.Errorf("error in grpc.Dial: %w", err)
 	}
 
 	return &GrpcClient{client: cl.NewExternalCalculationClient(conn), connection: conn}, nil
@@ -48,7 +48,7 @@ func NewGrpcClient(url string, logger logr.Logger) (*GrpcClient, error) {
 func (c *GrpcClient) Calculate(ctx context.Context, list *cl.MetricsList, logger logr.Logger) (*cl.MetricsList, error) {
 	response, err := c.client.Calculate(ctx, list)
 	if err != nil {
-		return nil, fmt.Errorf("error in externalscaling.Calculate %s", err)
+		return nil, fmt.Errorf("error in externalscaling.Calculate %w", err)
 	}
 	return response.List, nil
 }
diff --git a/pkg/scaling/scale_handler.go b/pkg/scaling/scale_handler.go
index f2f66d93be7..61c04d7cbd9 100644
--- a/pkg/scaling/scale_handler.go
+++ b/pkg/scaling/scale_handler.go
@@ -810,12 +810,12 @@ func calculateComplexLogicFormula(list []external_metrics.ExternalMetricValue, f
 	}
 	program, err := expr.Compile(formula)
 	if err != nil {
-		return nil, fmt.Errorf("error trying to compile custom formula: %s", err)
+		return nil, fmt.Errorf("error trying to compile custom formula: %w", err)
 	}
 
 	tmp, err := expr.Run(program, data)
 	if err != nil {
-		return nil, fmt.Errorf("error trying to run custom formula: %s", err)
+		return nil, fmt.Errorf("error trying to run custom formula: %w", err)
 	}
 
 	out = tmp.(float64)