stealth+invisible VS hunch

[Daiyang]

core book page 563: "A creature can generally notice the presence of an active invisible creature within 30 feet with a DC 20 Perception check. The observer gains a hunch that “something’s there” but can’t see it or target it accurately with an attack."

this rule seems to me that makes any stealth roll useless.
imagine a master infiltrator rogue with 20 ranks at stealth trying to move past some guards(10 ranks on perception). drinks a potion of invisibility, that gives him +20 on his roll. then rolls a 20. thats a 60 DC on perception ckecks for the guards to notice him, olmost impossible!!! BUT theres the damn HUNCH, with DC only 20 the guards think thats something there.
then the rogue says, next time no invisibility potion, only stealth!!

i clearly dont understand the benefits of invisibility on stealth/infiltrate if a zero level blind/paralyzed/deaf/mute or whatever else humanoid(or not) has the HUNCH. except if this 20 DC perception check doesnt apply on stealthed creatures, ONLY invisible.

any thoughs??

[SlimGauge]

Wrong forum. This is not a rules question. Thoughts are not rules answers.

However, I will say that you can't stealth while observed. Invisibility makes you not observed. That's why you don't just skip the potion in your example. You would be automatically spotted if you just stealth through the guards field of view without being invisible.

[Daiyang]

it is a rules question, just not a clearly one.
im just asking if that "hunch" in page 563 "breaks" all your stealth skill if you are also invisible while stealthing.
* the source of the invisibility -potion, spell, power- is irreverent.

its seems to me a 20 DC check is a bit low for supernatural HUNCH that everyone has.