Lower-than-expected holiday iPhone sales and a weak revenue forecast by Apple Inc renewed fears about Chinese demand and a tepid global market, wiping 8 percent off company stock. This year was to have been Apple Incs watershed moment in China, when a long-awaited deal with the nations largest carrier was to have propelled it back toward the top ranks of its most crucial market, clawing back ground from rival Samsung Electronics. Instead, the forecast for the March quarter – when Apple is expected to have reaped the fruits of that long-awaited deal – raises questions of whether investors had over-estimated that arrangement, and broader concerns about flagging demand for smartphones and tablets in general. Theres no doubt that shipments (to China Mobile) are lower than almost anybody expected, said Pacific Crest Securities Andy Hargreaves.