Just two weeks after lowering its Brent oil price estimate to $80 per barrel for the fourth quarter, Morgan Stanley cut again its forecast, now expecting the international benchmark to average $75 a barrel in the last quarter of the year. Analysts at Morgan Stanley see rising headwinds on the demand side, which has been their key reason for cutting their Q4 oil price forecast. “The recent trajectory of oil prices has similarities to other periods with considerable demand weakness,” Morgan Stanley analysts wrote in a Monday note carried…