Seat Position or position on seat!!!

Just a quick one. I have noticed that while I am down in my aero position, I have the tendency to creep forward on my seat while I am cycling. Although this initially feels more comfortable, I am realizing that I lose a lot of efficiency. As I consciously move myself back, I feel a serge in extra power. This is something to note. I may need to adjust my seat position backwards to help but I am not sure yet. I will give it a go and see what happens.