(In chapters 11-19) Why does Miss Havisham command Joe and Pip to meet with her? What does Pip's attitude toward her offer reveal about his changing sense of values?

Joe accompanies Pip to the Satis House the next day. Miss Havisham gives Joe twenty five guineas for Pip's service to her and thus buys Pip's indenture as a blacksmith. Pip is take with her wealth and ability to hand out money.