I think, but really not certain of this… if you chose the base sim, I think only the base content is installed, with additional content being available in the market place. If you install the premium i think the additional content is also installed.
The only reason I say this is because I am pretty sure I originally installed the premium deluxe version and do no recall having to download the additional content separately. When I had some sim issues I believe when i carried out a clean install I initially just installed the base sim to rule out additional content as the problem.