Narcissa's face went from jovial to horrified. "Severus, no! I thought you'd be able to treat this easily!" She looked up to Severus" arithmantic equation and fine-tuned the variables and re-ran the equation, and the red line turned black at the fifteen year mark. "You know how unstable that potion is and the kind of price that comes with it! Look, he can lose up to eighty five years of his life essence if you let him do this!"