That's strange then, because this "hidden accuracy bonus" seems to vary then. In the screenshot I originally attached, Eder is about 7th or 8th level and the "hidden accuracy bonus" comes to +8. In the game I am playing now, his total secondary deflection is 42 (+30 for Fighter, +3 for Perception, +12 for Level, -8 for Larder Door shield) so that implies the "hidden accuracy bonus" is now +5. He's 5th level. Is this a bug or does this "hidden accuracy bonus" scale by level or something?