So I'm trying to understand the way skill bonuses are calculated for monsters to understand if it differs at all to NPCs and PCs. Currently I'm trying to work out how the skill bonuses for a Bugbear calculate, just as an example and also because I'm advancing one with a Half-Fiend Template (everything else has been calculated already).
A standard Bugbear has 3HD and an Int modifier of 0 for a total of 6 skill ranks (2/HD for Humanoid creatures). Its stat block lists Intimidate +7, Perception +8, and Stealth +10. Subtracting the +4 racial bonuses to Intimidate/Stealth and +1 Dex bonus to Stealth leaves me with +3 Intimidate, +8 Perception, and +5 Stealth. Subtracting the feat bonuses to Intimidate and Perception results in +0 Intimidate, +5 Perception, and +5 Stealth, and Intimidate goes down to -1 because of the Cha penalty. Finally, removing the class skill bonus from perception and stealth granted by Stalker (Ex) leaves me with -1 Intimidate, +2 Perception, and +2 Stealth.
If my calculations are correct (which they might not be), the remaining points should come exclusively from skill ranks - balancing all three to 0 requires only 5, meaning one skill rank goes unused. Is there something I'm missing, or do monsters just have different rules I'm not aware of?
Sorry for the arbitrary question - I just get curious about the finer rules and like to know how things are calculated.