How to "correctly" reduce downtime with Cloud Foundry deployments?

Question

I am using Blue-Green deployment in order to reduce deployment downtime of a Cloud Foundry application (NodeJS). I am using BlueGreenDeploy plugin for the Cloud Foundry Command Line Interface (cf CLI) (https://github.com/bluemixgaragelondon/cf-blue-green-deploy) and my app is running several processes for single instance employing PM2 Cluster Mode.

Everything is working fine but I want to know if there are some "Best Practices" or things I am not doing correctly.

For example: does it help if I manually scale-down my application to only 1 instance before to push my application? App instances are specified in the manifest file so it is CF itself that manages the scale up process.

Thanks in advance to everyone who will help me.