Procter & Gamble's Tide detergent can be seen on display at a new Wal-Mart store in Chicago January 24, 2012.Procter & Gamble on Tuesday reported mixed quarterly results, but the company's volume increased for the first time in more than two years.Volume excludes pricing, making the metric a more accurate reflection of demand than sales. Over the last several years, P&G's price hikes across its portfolio, from diapers to detergent, fueled its sales growth, but volume flattened or even declined as consumers ...