There may be some confusion here regarding the start procedure on the 777 APU? Currently there is an operators bulletin TBC 79R1 that talks about the correct method for starting the APU.
"When starting the APU, position the selector to Start and hold for 1 second, then position the Start selector to ON manually. Do not alllow the APU selector switch to spring back to the ON position".
Not aware of any of the other methods described as being a part of any formal Boeing procedures.