Basically, the accuracy of the shooter determines your overall chance to hit. That's why we can state that accuracy determines chance to hit.... because it does.
But you're wrong because it doesn't work like that. Accuracy IS NOT WHAT ALLOWS YOU TO HIT A TARGET...EVER.
Using this example I'll prove it:
This is a good example. But lets flip it around. Lets say the target is visible and right in front of you, but you're a highly inaccurate shot. Your overall chance to hit is reduced by your poor personally accuracy.
Except in the situation I explained above it doesn't matter what you're accuracy is, you're still only have a 49% chance to hit the target.
So feel free to jack up the perception all you want, in fact set it at 20 if you want, you're chance to hit will remain at 49%.