Alton77, without immersing myself too much into technical aspects like predictions etc. There's one golden rule in aviation "do it as per SOP" unless safety dictates otherwise. Often it's beyond our understanding or even intentionally left out from explanations in order to make the pilots life actually easier one. Just as a axiom there's no need for a reason to follow meticulously the SOP. In fact it was written using bad experience of others, that's reason enough for me.
Cheers
