Check your calcs for Trial of Sekhemas...dmg

I just tried a run and oh boy was that abysmal!!!!! 2nd affliction I got was -40% dmg. Continue to run not bad, bought a boon for +50% dmg. But absolutely NO improvement to dmg dealt. So, please check the calcs and how a -40% + +50% = +10% dmg can meet up, as I saw this for the entire run still stuck at -40% with no improvement with the +50% boon