Extraído de un post de un moderador del Foro Oficial de Sacred 2:
EP gives a bonus to Magic Find that affects all item drops from monsters, despite the tooltip not displaying it until you reach the Mastery (& yes, I've posted that as a tooltip bug).
EP Mastery gives you a better chance to find nice stuff from chests/barrels/magical hiding places (as it says that's the "find a hidden compartment" bit in the description).
EP (apparently) helps to uncover invisible foes from a closer distance, though the only ones I'm aware of are in the Unique Mount quest.
EP does not affect the quantity of item drops (it lets you find better stuff, not more stuff, that might be why they moved the "is an item dropped at all" bit out of #2) & it does not help you find more magical hiding places.
Lo que viene a confirmar lo que muchos sospechabamos, que Percepción Mejorada SÍ que afecta a los drops de los monstruos (además de los cofres), a pesar de que no lo ponga en la habilidad hasta que llegas a maestría(seguramente lo corregirán en próximos parches).
Eso si, aumenta la calidad de los drops, pero no la cantidad.