you do right to use only the supplied charging accessories,i personally take no chances with my expensive devices.Thanks for your feedback. I think I will stick with the safer option is to use the accessories accordingly.
I appears the iPad charger produces output of 2.1A where as iPhone charger output 1A. Both outputs same voltage but at different Amperes.
I suppose if I use iPad charger on an iPhone it will act as a fast charger.