If you mean how much you get back, level 1 t6 is 8b, level 2 is 18.4b, level 3 is 30.88b and level 4 is 44.6b
20% back. Remember if T6 Lvl1 costs 40b and T6 lvl2 52b, evicting a T6 lvl2 would cost 20% of 92b. The answer is 18.4b. This means you have to add all level on that certain tier to get to your level and multiply that answer by 0.20.