Here is how it works: Lets say you are in a long position with a lot size of 6.13 lots. Now you get signal to go short. What will happen is your long position of 6.13 lots will be reduced by 6.13 lots. This then would mean that your long position lot size is now equal to zero and your long position would be closed. Now lets take another case. Let’s say you have set the reduction lot size to 1.0. Now when you get a signal to go short your long position would be reduced to 5.13 lots and you would still be in a long position instead of a short position because you still have a long position with a lot size of 5.13. Now lets take another case. Let’s say you have se the reduction lot size to 7.13 lots. Now when you get a signal to go short your long long position of 6.13 lots would be reduced by 7.13 lots. Since your long position only has 6.13 lots this would mean that your position will be changed to a short position with 1.0 lots.