Actually, no it isn't.
If maximum manual braking will stop the aircraft in the required distance, all reverse thrust will do is lessen that requirement and keep the brakes cooler.
The only time reverse thrust will decrease the available landing roll is when it is used in addition to the maximum amount of wheel braking available.
Clearly, in cases where wheel braking is less effective due to runway conditions, this will be more relevant.
Last edited by Wizofoz; 9th June 2013 at 17:11.