That adage is meant for tasks that require a large amount of coordination, e.g. large software projects. This is no such task. It's like saying you've got a la

That adage is meant for tasks that require a large amount of coordination, e.g. large software projects. This is no such task. It's like saying you've got a large wall that needs to be scrubbed clean, and having 10 people do it at once would be slower than having one person do it. That is obviously not going to be the case.