There are several reasons this could be happening. Possibly too much throw on the rudder and elevator making it get buried deeper than it needs to be. Another might be cg... for your case if throw isn;t the problem I would guess that the cg is too far aft.

To check throw try doing just aileron and rudder on the down and see if it comes out of that cleanly... if it does remove a lot of your elevator and then try again with elevator. You can also experiment with leading with elevator and unloading the elevator before the snap is finished so it will come out where you want it to.

But basically you just need to make single small adjustments every couple snaps and see if it looks like it is getting better or worse. Also be sure and continue to do your other snaps to make sure they aren't looking any worse when your downline snap is looking better with your adjustments.

Hope this helps

John