Personally, I think expats are different from foreign nationals on local terms. At least, in my previous company, we separated these two. Expats are of high management positions and usually have high salaries while being provided with cars and housing.

On the other hand, foreign nationals on local terms may or may not get a housing allowance and would have a much lower pay. The Japanese & Koreans in my previous company came to work in Singapore on local terms so they had to bear housing costs by themselves.

One Japanese friend of mine who is working in Singapore on local terms is taking home relatively good pay but still bearing the rent on his own. (Takes away quite a portion of his pay.)