I can't see that will make any significant difference. The nut will
tend to compress the back of the olive and also drive it into the gap
between fitting and pipe which compresses the front of it. The forces
on both sides will be largely similar and in balance. From a sealing
point of view its the front face that's closing the gap between pipe
and fitting that is doing the work anyway.



....but the front of the olive can only close up if it can slide further
down the pipe.