I'd be happy to help!
You are a clear, direct writer, which is great benefit for AWA. That's what they like to see. Also, you organized your essay so that it is logical and easy to follow. Finally, you tackle the prompt directly and do a nice job responding to the prompt.
To improve, you need to add more detail to your body paragraphs when you explain a flaw. For example you say:
"...For the profit margins to be improved there must be changes in the revenues, in the costs or in both the revenues and the costs. The author argues that this plan will work on the grounds that it will reduce the product's life cycle costs to the company."
So you tell the reader that revenues and costs must change. Then you mention that the plan will reduce the products life cycle costs. So what is the connection between these two statements? Can you give a reason or detail about what types of things effect revenues and cost? Can you tell the reader why reducing the life cycle of a product will not effect revenues? Answering these questions and including them in your paragraph will add a range of depth and critical thinking to your essay that it lacks a little bit right now. Your examples and analysis are brief and slightly superficial. I know that you have a limited amount of time, but to raise your score, you'll need to add more detail.
I hope that this helps a little.
Magoosh Test Prep