Yes, im not sure on the exact math, but you can search the internet for it.
What i remember is that even lower levels can see stealth depending on distance to target, if the target is in front of you (180 degrees cone or something) and time. Then there are items and talents that increase someones stealth level by 1 level or more as if they were a level higher themselves. This influences the spot-check so that there is a better chance of you staying undetected.
If you have no feral instinct talent and you stealth around in front of a mob, the distance to it and time you stay in that location determines of it is going to spot you. If you are lower level or the mob/player has stealthdetection bonusses its chances increase to spot you, if you have feral instinct your chances increase of staying undetected and thus you can move in closer.
If you are in stealth and sit still long enough just in front of a lower level mob, it will still spot you at some point.
If you are level 1 and sneak up behind a level 80, the level 80 won't spot you, because you are not in his front (180 cone).
If you and the target are equal level 70 and you have 3/3 feral instinct, but the target has +2 stealhdetection, it will be as if you are a level 73 stealth and he is level 72.