Oh yeah, you are right about that. Fimming, topping, and LSTing are techniques that promote smaller, denser growing plants. It forces the plant to focus energy in the remainder of the plant. I believe they are all forms of super-cropping. (What do you do? Who me? I'm a super cropper! They call me super cropper man.)

I'm not sure that you fim or top more than once although I guess it could be done multiple times during veg. I really don't know the answer to that. You would not want to be doing any seriously trim work during flower except to remove fan leaves, lower and / or dying leaves, and lower stems that do not get enough light to produce.