FAR 121.195 states....no person operating a turbine engine powered airplane may take off that airplane unless its weight on arrival, allowing for normal consumption of fuel and oil in flight (in accordance with the landing distance set forth in the Airplane Flight Manual for the elevation of the destination airport and the wind conditions anticipated there at the time of landing), would allow a full stop landing at the intended destination airport within 60 percent of the effective length
So getting back to the original question, once you are inflight you can forget about the 60% rule whilst applying corrections.
I assumed that as Global Driver is based in Tel Aviv, he most likely isn't operating a JAR registered aircraft.
Following the Swissair MD11 crash, aircraft manufacturers very rapidly stated producing ACTUAL landing distance charts in their manuals together with DISPATCH charts, there is nothing on these charts stating that they can only be used in Emergencies as their use is permitted by FAA regulation.
Mutt