The reason is because I am using fargate and before I was setting the CPU for each container and I ended up with 1024 CPU units and 2048 MiB of memory which was way too expensive from previous versions (using pure EC2). I want to do this because this way I minimize costs because for eveyone I would have the same 256 CPU units. Whereas with another TaskDefinition I would have to set the minimum CPU units again which with the other TaskDefinition sums (256+256) = 512 units