This whole business of lipo cut off voltages is very vague it seems to me.I have also come across this 2.5v/3.0v contadiction
As I understand it,3.0v is the cut off value for no (or very little) current. 2.5v allows for the voltage drop under high (motor on)current conditions,to allow for the voltage drop caused by the I R of the cell.(I stand ,and am prepared, to be corrected)
Actually I have not found this to be a problem,as by the time 3.o v is reached ,the power,and perfomance drop off encourages one to land anyway.