"Stealth Orbitals : High energy hide-and-seek. +10% per rank increase in orbitals avoiding detection" -
I am assuming the bonus multiplies an already established "Stealth strength"? Like the base strength is 10 and having the skill at rank 5 would give you a strength of 15 which is rolled against by someone trying to detect you?

Or is the bonus percentage the strength where with rank 9 you would have a 90% or 100% chance of avoiding detection.