An RAE cannot be directly converted into an IU without knowing the source(s) of vitamin A. For example, the RDA of 900 mcg RAE for adolescent and adult men is equivalent to 3,000 IU if the food or supplement source is preformed vitamin A (retinol).
Diploma vs Associate Degree. A Diploma is one type of certification, and an Associate degree is another type. Diploma and Associates degree, as the name specifies, are different in many aspects. There is no confusion between the two, as the difference is very specific. A Diploma can be said to be a document awarded to a student after completion of a course.
I cant tell you much about diplomas as I am a B.tech myself. But the main difference between a post graduate diploma and an advanced diploma is that a post graduate diploma as the name suggests is a PG diploma, whereas advance diploma is same as the regular diploma only that its a 3- year degree course as compared to a 2-year regular diploma.