Boofhead,
It is quite possible that I may have missed something here ...
(a) which design standard imposes the 15 percent pad on AEO ASD ?
(b) a significant difference between AEO and OEI reject is the maximum speed achieved during the acceleration and reject sequence. In the AEO case, the reject will see a higher maximum achieved speed and longer distance to stop .. one of the main hazards in rejecting from high speed for other than a failure on a limiting runway.
(c) while the current rules require the 2 second pad, which provides a bit of a buffer, I would question any suggestion that a reject from V1 on a limiting real world runway involves any sort of guarantee that you will actually get away with it .... especially on a pre-amendment 42 certification aircraft .....