My score on the actual AWA was 6. The essay is good, but can be improved. Here are my suggestions:
1) Consider making your first paragraph more precise by stating that there is more than one faulty assumption, and that the conclusion itself is unsupported. Moreover, make sure to use the correct pronoun (you used "he" instead of "it") and don't forget to use "the" or "a" before certain nouns. See my edits below:
The argument claims that the company’s revenue is declining due to delays in their manufacturing. He It holds the purchasing manager responsible for poor planning to source raw materials, which ultimately is causing delay in the manufacturing process. Hence, the purchasing manager should be transferred to the sales department and be replaced with a scientist as they have he would havebetter knowledge of metals. The conclusion of the argument relies on assumption for which there is no clear evidence. This argument relies on assumptions for which there is no clear evidence. By drawing on these assumptions, the conclusion itself lacks strength and is questionable on several grounds.Therefore, the argument is rather weak, unconvincing and has several flaws. 2) In your second and third paragraphs, use "For example" instead of "E.g."
3) Take note that the present perfect tense (have been) should be followed by the past participle (strengthened). See my edit below:
This claim could have been strengthen strengthened if the argument provided evidence that purchasing manager has an experience in sales and that he has been failing many tasks in current role.
How your score will be calculated:
Your essay is very well structured, and is easy to follow. You will be rewarded for doing this by the AWA grading system. I doubt you would get anything less than a 4.
One improvement you can make at this point is to increase the word count. Do this by strengthening each of your points with multiple examples. (Right now, you are only using one example to support each point.) In my experience, the AWA grading system rewards length and penalizes brevity.
Another improvement you can make is to improve your grammar. In my opinion, you are still lacking familiarity with tenses, pronouns, and articles.
If you fix your grammar, you would probably get a score between 4 - 5 with your current essay. If you fix your grammar
and increase your word count, you may get a perfect score. After improving your current essay, I suggest you test your AWA ability by purchasing GMAT Write, which uses the same software to calculate your actual AWA score on the GMAT:
https://www.mba.com/global/store/store-c ... write.aspxAll the best.