diff --git a/docs/development/plugin-triggers.md b/docs/development/plugin-triggers.md
index 3d89f2ce8..1181a9cff 100644
--- a/docs/development/plugin-triggers.md
+++ b/docs/development/plugin-triggers.md
@@ -1833,7 +1833,7 @@ set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
 
 - Description: Sets the scale for an app based on a specified formation (process-type=quantity). Any unspecified process types will be left as is.
 - Invoked by:
-- Arguments: `$APP $SKIP_DEPLOY [$PROCESS_TUPLE...]`
+- Arguments: `$APP $SKIP_DEPLOY $CLEAR_EXISTING [$PROCESS_TUPLE...]`
 - Example:
 
 ```shell
diff --git a/plugins/app-json/functions.go b/plugins/app-json/functions.go
index 7ca481fc4..41f671295 100644
--- a/plugins/app-json/functions.go
+++ b/plugins/app-json/functions.go
@@ -496,7 +496,9 @@ func setScale(appName string, image string) error {
 		return err
 	}
 
-	args := []string{appName, "true"}
+	skipDeploy := true
+	clearExisting := false
+	args := []string{appName, strconv.FormatBool(skipDeploy), strconv.FormatBool(clearExisting)}
 	for processType, formation := range appJSON.Formation {
 		args = append(args, fmt.Sprintf("%s=%d", processType, formation.Quantity))
 	}
diff --git a/plugins/ps/src/triggers/triggers.go b/plugins/ps/src/triggers/triggers.go
index bad436b7b..b1581f446 100644
--- a/plugins/ps/src/triggers/triggers.go
+++ b/plugins/ps/src/triggers/triggers.go
@@ -86,7 +86,8 @@ func main() {
 		appName := flag.Arg(0)
 		appName, args := common.ShiftString(flag.Args())
 		skipDeploy, processTuples := common.ShiftString(args)
-		err = ps.TriggerPsSetScale(appName, common.ToBool(skipDeploy), processTuples)
+		clearExisting, processTuples := common.ShiftString(args)
+		err = ps.TriggerPsSetScale(appName, common.ToBool(skipDeploy), common.ToBool(clearExisting), processTuples)
 	case "report":
 		appName := flag.Arg(0)
 		err = ps.ReportSingleApp(appName, "", "")
diff --git a/plugins/ps/triggers.go b/plugins/ps/triggers.go
index fbd7ae922..49b631f1d 100644
--- a/plugins/ps/triggers.go
+++ b/plugins/ps/triggers.go
@@ -315,6 +315,6 @@ func TriggerPsCurrentScale(appName string) error {
 }
 
 // TriggerPsSetScale configures the scale parameters for a given app
-func TriggerPsSetScale(appName string, skipDeploy bool, processTuples []string) error {
-	return scaleSet(appName, skipDeploy, true, processTuples)
+func TriggerPsSetScale(appName string, skipDeploy bool, clearExisting bool, processTuples []string) error {
+	return scaleSet(appName, skipDeploy, clearExisting, processTuples)
 }