Nikon Capture Question

Fishead

.....I've been using capture 4.0 for awhile but I'll have to admit being a bit of a slow learner when it comes to a lot of pp stuff......too old to (easily) learn new tricks I guess! Anyway I have found the levels control to be of great help in adding punch to photos but I am confused by the white point and black point settings.....do they basically do the same as the level sliders, and if not, are they used after setting the sliders?
.....One more question. The tutioral here on using USM was very helpfull and insightful to me, however it suggests to take the amount slider to 500% to start and while my beginer PS ("Elements" 4.0) goes to 500 Capture goes only to 100% so the rules for using USM here must be slightly different? Hoping some kind person here can help me out, as the camera forum I lurk on is to too snotty to be bothered with such newbie questions. Thanks in advance allen

Coolpix990, d-100, d-200