Barney Gumble is a sales professional who goes to work for Duff Beer Group. Duff has a sales force that sells to independent liquor retailers, and whose members are paid largely on commission. At the time Barney is hired, Duff's standard commission paid to the sales professionals is 6 percent.

On his first day, Barney is welcomed by Montgomery Burns, the company's Vice President for Sales & Marketing. Burns tells Barney that the Sales Manager, Lionel Hutz, will give him all the details about his new job. Barney subsequently goes to Hutz's office, where Hutz tells him all about the job. When they get to the discussion of commissions, Hutz tells Barney that in one region, Shelbyville, Duff has had trouble penetrating the market, and that while the standard commission is 6 percent, Barney will get 8 percent commission on all sales within that region.

Time goes by, and Barney is successful selling, but Duff pays him only 6 percent on all his sales, including those in Shelbyville. Barney later quits to pursue a singing career and sues for the extra commission he claims he should have been paid.

What is the likely result of the lawsuit? Describe each theory on which Barney may be able to recover from Duff.