Cargo carrier and tongue weight reduction??????

My trailer has a huge cargo bay in the rear bedroom area and I put a whole bunch of weight back there. Firewood, 3 bikes, drinks, probably well over 500 lbs. It takes my tongue weight from almost 1200 lb to about 1050. There seems to be a law of diminishing returns, though, because at some point, more weight doesn't equal proportional reductions of tongue weight. Not sure if spring compression comes into play or what. It will help, just a question of how much.