Cumulative Spin in a Rally

I see it mentioned that a chopper "loads" a ball with backspin, or a loop "loads" the ball with topspin.

How much spin is lost with each hit in a rally? If two players are using opposing shots (chops vs topspins) does the net "spin" in a rally stay the same?

What about two players of the same style? Can you rely on your opponent's spin?

Hi Frank,

If one player is putting topspin and the other is putting backspin, the ball actually stays spinning in the same direction just travelling in a different direction so the spin can increase.

Today's game allows the players to generate their own spin on the ball by using good rubber with lots of grip and then with a fast swing the ball goes in the direction and with the new spin.