Certainly sounds better than 200ft...
Anyway this is the way it should be calculated.
TORA/TODA
90° Entry
Rm + X
180° Entry
Rn + Y
ASDA
90° Entry
Rm + X + Wb
180° Entry
Rn + Y + Wb
Where:
X = Safety distance of outer main wheel during turn to the edge of runway.
Y = Safety distance of outer nose wheel during turn to the edge of runway.
Rm = radius of turn of outer main wheel
Rn = radius of turn of outer nose wheel
Wb = Wheel Base
Good Luck.
Mutt