...ok, in the first table you've to apply a decrement versus T.O. config, RWY length and clearway availability. I understand this weight decrement is because of the contamination. Right below there's an other set of tables, one per each T.O. configuration and, in there, you've to claculate once again a corrected weight which is used thereafter to get T.O. speeds. What's the reason for this new weight decrement? Vmc limitation ?!?