I think there was some talk regarding that back when people were running palace all day, back before SE tweeked the chest. Something of the sort that the higher your level is, the better chance the silver chest wont explode/ will give you a better chance at +1.
With all the sneaking, i dont think the new method can test this out correctly running even hundreds. Though the older runners pre-chest tweak might be able to clear this up.
I think this was one of the reasons why we wanted to kill most mobs.