Gangjee, starting at one-under 215, ended at one-over 289 and now only has one tournament left to get back to top-10 on the Money List and qualify for the lucrative CIMB Classic later this month.
Taking the title home was England's Steve Lewton (71) who held his nerves together and won by two shots despite a closing bogey in the final round. He totalled five-under 283.
Gangjee birdied the third and fifth and was very much in contention before he ran into a double bogey on par-3 eighth and then dropped bogeys on 11th, 12th and 17th.
Despite a birdie on 16th, his chances had ended well before that.
As of October 20, the leading four golfers from the Order of Merit will earn starting places in the USD 8.5 million HSBC Champions while the leading 10 players will qualify for the USD seven million CIMB Classic.