The scene on the golf course was on a Saturday and the next scene is the next day when Jameson Whitworth said a stock he was going to buy dropped 10 points. The stock market is not open nor do stocks change value on a Sunday.
Mr Jameson hits a hole-in-one on the golf course. Phil offers to buy him lunch to celebrate. However, the tradition is for the ace golfer to buy drinks for everyone in the clubhouse.