I did some testing on the bonus tier with just Bastilla and Kanan in the party under First Order Officer lead
All scores were recorded without offense down on Kanan or using Bastila's assist special and Sith Trooper had Defense Up on all hits by Kanan
Kanan (damage values with 200% protection up) - (All attacks were critical hits)
1650 1708 1694 1733 1585 1710
Kanan's Damage Output after losing the protection up - (All attacks were critical hits)
1196 1285
you multiply the damage with 1.35 and its matching up with the variance I was getting with protection up buff
EDIT: Didn't keep track of the tenacity up working as it should