However, a bo3 with PartinG up one game (in my opinion the best answer), puts it at 75% (roughly) chance of PartinG to win the series. In this scenario, PartinG only loses 5% equity (MKP gains 5%).
Even if MKP were favored as much as 60% against PartinG (I think this is pretty generous), the decision between a regame and a win awarded to PartinG is a wash (20% equity). The bo3 would give PartinG a 64% chance of winning. Thus losing 16% equity (which is still less than 20%).