As the winner of the battle in the Harvest Square, there was indeed no need for the young Lin Li to negotiate with anyone. He only decided to come not because of William or the Time Consignment Store, but because he was interested purely in the formulas.
In fact, Lin Li could easily snatch the formulas from the Time Consignment Store if he really wanted to. There was nothing William could defend himself with, especially since Lin Li had the ability to defeat Vidas.
William scolded himself for being silly in his head. Why did he even pull his business tactics on the 20-year-old Lin Li? Wasn't he just asking for death!?! He coughed awkwardly, and adjusted his mindset before respectfully saying, "Master Felic, why don't I supply the formulas and herbs, while the Tower of Dusk carries out the formulation? You shall have 60% of the proceeds while I take 40%. Will that do?"