Temporary work permit 2nd time

Dear Anil
I finished my Degree and got 2 yrs Graduate work permit. When I finish that I intend to do Masters Degree again. Will I get 2 yrs. Work permit again or they give only once?
Immigration point calculator says 5 point applicable for other studies (apart from my Australian Degree level).
What is this for (not Naati). Does that mean i should learn something else (apart from my Accountancy Degree).

Appreciate your support .

Best regards