from what i realised so far, if you hurt the plant a bit (a little scratch, some tear on the stem etc.) that makes the plant produce more....i guess topping it although it produces two colas, it is one way of hurting it i suppose.....during my grow i LST them as well....in one plant i pulled it down too much.....it was bent a lot downwards and accidentally the stem was broken...not very much but a bit broken.....this plant recovered quite well, very fast and now is the best and most promising above all, even from the one with the 20 tops/branches....in my photos: http://boards.cannabis.com/showthread.php?t=14998 it is the plant in the front, right side with the big cola on top