What you are showing is that you doubled the capacity of your winch. If you are pulling an 8,000 # load with a single line, the line line pull will be 8000 lbs. If you are pulling the same 8000 # load with a double line, the line pull will be only 4000 lbs. You basically were showing the same thing. By doubling your line you can pull twice the weight or half your line pull.
If you hook a 6000 # wt to your 8000# winch your line pull would only be 6000 #'s (plus friction etc.) - Brad
If you hook a 6000 # wt to your 8000# winch your line pull would only be 6000 #'s (plus friction etc.) - Brad