Boeings Takeoff guide(I can't remember the correct title)developed in the early (90's(maybe 80's)by an FAA need for reeducation of the Industry,due to reject cockups at the wrong time and the suspect rejecting stopping capability of the DC10.In said publication it became evident that more 'critical' rejects had been sucessful due to the Captain's easier, transition of control, with the Captains hand on the Throttles /power levers.This did not preclude the F/O from calling"reject/stop"(as per the SOP's).
A lot of European carriers had the policy of the F/O completing the rejection,but more of the Industry adopted the policy of the Captain closing the Throttles,and completing the stop.
On the F/o's takeoff,once he/she had stood the power up to the takeoff setting ,the F/o would relinquish control of the power.On the captains T/Off,the F/O would finetune the takeoff setting,and get their fingers out o'the way..
