Hermione nodded enthusiastically, "Oh, yes, I understand completely. You can't start throwing your money around just because you're... friends with someone." She hoped they were friends. Having tea with someone kind of indicates that, right? That and she didn't want to be presumptive. "That could work, too. I can write up the propositions and teach you all the necessary facts in person. That way you can ask questions, as I'm bound to leave something out."