oups, typo, the script I was trying to link is named 'getstarted', but if you have confirmed your setting is already at max then it won't help.
It would seem that your dock is just not playing ball, or seem to exit out of bootloader mode prematurely. The last suggestion I can make is to use a micro-USB to USB cable as short as possible and substantial shielding, if you have anything of that description at hand.
... I do REALLY recommend you invest in one of the official PSU though, not all of them are created equal and I have had myself some unexpected results with other 2A rated power supplies and the Pi3, though admittedly I am pairing it with the touchscreen.