Question about chance to avoid stun

Wiki says baseline to avoid chance if you have any energyshield is 50%. Now if i add 5 tattoos of the tasalio tideshifter (10% chance to avoid being stunned) - i should be stunimmune , right?

PoB says with 5 tattoos equipped 75% and with 10 tattoos equipped 95%. Confuses me because it clearly is a flat chance not some increased chance on the tattoo, right?