Lost Coins - What Did I Do Wrong?

So I wanted to sell my BCHA before it goes to nothing. I created an account on an exchange that supported BCHA and sent a test amount to the exchange wallet to verify everything was working right. I received both coins on the exchange. I then withdrew the test amount to verify I could get my BCH back and that worked too. At this point I thought maybe I screwed myself. The BCH coming back to my wallet had 1 confirmation. So I sent the remain amount in my wallet minus the test amount and a little extra just to be safe. But this time I didn't get the BCHA split, just the BCH deposited in my exchange wallet. So my question is how should I have done this so I didn't lose the split BCHA on the second transfer? Did I have to move all my BCH to a completely new wallet or just not send the BCH back from the exchange before I sent the full amount?