If your at the point where your stealth is around 80, I EXPECT him to be good enough to unscrew rusty bolts unheard, to dance around guards with ease, break into nigh anything.
Your skill in move silently may be 80, the grate's mooring is not. Your hide skill might be 150, you still occupy physical space. Standing in front of someone's face is beyond abusive to the point it's absurd. Stealth is *not* a supernatural ability, even HiPS (which is) will NOT let you do anything of the sort. Nobody no matter at how good they are at hide and seek can do this sort of nonsense.
As for breaking into anything, stealth has nothing to do with open locks and disable device.
Properly coded, stealth should unstealth you if you get within a very close range of people just because abusive players will rationalize anything with nonsense, even as they push through a tightly-packed monster encounter in a small, bare corridor or through a doorway which is opened for 1 second with a person standing in it on the second floor of an inn.
"Oh well I went in through the window!" (cheesing) "Oh okay then, I dumped shards of broken glass all over the floor under it to the point it's unavoidable, also coated the sills with grease and also got a room who's window is a little more than an arrow slit." (no reason why not, after all, one character is making up reality, there's no reason the other should be exempt since all of it is perfectly plausible)
If a person is mindful the window is a weak-point, there's really no way you're going to get in without them noticing. Hell just opening a window is glaringly noticable in a 15' square room, especially given outdoor noise beyond your control, Barovia's lovely chill climate, the fact you'd have to open the shutters (which are all up on these sorts of buildings) and still somehow bypass reinforced window grating.
Stats never triumph logical thought.