MD-11, PROF, and ATS system question

[DAL2728]

I was talking to an MD-11 pilot the other day who flies for World Airways and he told me it was company policy to arm NAV on the ground but PROF at 400ft AGL. When I asked why they didn't arm PROF on the ground as well he told me that if PROF is armed the throttles are advanced too far forward the ATS might interpret it as a takeoff.

I didn't think to ask for more details of him at the time but perhaps you all might help. My question is, at approximately what power setting will the ATS clamp the throttles for takeoff power? It was my understanding that breakaway thrust for the MD-11 is about 40% N1 with any of available power plants. If you're simply taxiing the aircraft is there that much of a possibility of the power running away with you and setting to takeoff if PROF is armed on the ground?

Thanks!