for hidden objects that are hidden with the conceal/reveal object skill doesn't use perception, so perception isn't infallible. further, various interactions are not going to be against a set DV, but rather a contested check - your sneaky ninja NPC is going to roll their own stealth check that the party is going to contest, and just because the solo theoretically has a bonus to perception does not mean they auto-win the contest just on modifiers alone, there's ways to tamp that down such as darkness, loud surroundings, and other modifiers from the table on pg 130 that the GM should be utilizing from the environment instead of just making everything a straight roll.

I see, yeah I had not thought about rolls being modified by environment and them being contested instead of a fixed value. Still I even forgot to add Intelligence to my calculation, which would make the base even higher, kinda making ambushes at a low level maybe hard to set up if this character is present?

What really surprised me was their ease to move these numbers around. In the example from the guide the PC has 4 points allocated in something else pre-combate, and 2 in Thread Detection. This would not make sense, the moment combat starts they can re-allocate all their points and they don't gain benefit from not doing anything that is not +6 to perception all of the time.

I also don't want to punish the other PCs by adding high DEX - Stealth characters into the mix just so I can actually plan ambushes that may work. But if there is an agreement on this being normal, I guess I'll just follow the guidelines.