Can AWS CodeDeploy ECSAllAtOnce scale required instances?

Question

Context

For the last couple of weeks I have been trying my best to get to grips with AWS again due to having to build the infra for a new startup.

I am using AWS ECS so that the stack essentially runs off of Docker containers. To keep the deployment process simple, I've set up a pipeline (CodePipeline) which uses CodeBuild and CodeDeploy.

To use CodeDeploy on ECS you are limited to just the ECSAllAtOnce deployment configuration.

However, for the time being I am just running two ECS Instances (so I'm in two different AZs), but for the CodeDeploy to successfully run ECSAllAtOnce I am having to keep four ECS instances so that two are working and two are waiting for the next deployment.

Question

If possible: how can I get CodeDeploy to scale up/down required ECS Instances so that I am not constantly running spares?