Please make sure the part is not in hibernate mode. In hibernate mode, the chip may still take ~30 seconds, even advancing the timer. Set HibCfg = 0, and watch Status2.Hib = 0, then do the shutdown command and shdn timer write. All I2C should be suspended after the ACK from the FG on receiving the timer data. Please note that MAX17261 will not shutdown your system itself when RepSOC register reaches 0%. Our device will only report that RepSOC has reached 0% by entering into Shutdown mode. The host controller has to turn off the system based on the informaiton supplied by MAX17261.