Does negative physical power bonus also get halved?

If my physical power bonus is negative 14% (base Rogue) will it halve, like the example, into negative 7%? So, correct me if I am wrong here: Rupture base 20 + rare throwing knife with 18 damage halved to 9, so Rupture ends up doing (20 + 9) * (1 - 0.07) = 26.97? or does the scaling stay at -14%, meaning, Rupture ends up doing (20 + 9) * (1 - 0.14) = 24.94?