a) It doesn’t, because it’s an event-by-event output requiring your own post-processing (as I already wrote in my previous answer), contrary to DETECT that is conceived such as to allow for automatic plotting (by the way, your two DETECT cards are basically identical, so that one of the two has no point).
b) Clearly, if you take all cycles, you will have a better statistics.
c) You are getting a sequence of numbers, where each number represents the energy deposited in a certain Cartesian cell (whose index is also reported) after applying Birks law quenching (since you used TCQUENCH). Having this way at hand a sequence of data, you can calculate and plot their distribution.
As previously mentioned, the pulse height spectrum in your TARGET region is produced by DETECT after achieving a suitable statistics.
The USERWEIG card has no meaning if you do not code and link the comscw user routine.