What is the difference ? I happen to notice that one of my charger was set on lithe. Ion and the other was on Poly I must have been charging them like that for a long time and not have any problem! Or did I ! 

Lithium Ion settings will charge to 4.1V per cell. Lithum Poly charges to 4.2V per cell. Generally Lithium Ion cells have hard shells such as cell phone batteries or cylindrical cells like use in most laptops. Lipos like we use are soft shelled. Unless you don't have enough headroom charging to 4.1 volts per cell will not hurt them and my actually add some length of time to their lifespan.