I believe you are talking about two different ideas: average speed and instantaneous speed. Yes, it velocity is lower than time must be larger in the equation you listed... but that is the average distance in (distance)/(velocity)=time. Instantaneous speed in projectile motion must ALWAYS be less than it was to start with, because there is downward acceleration on earth. This acceleration decreased velocity, but you don't use x/v=t... rather, you used the kinematics equations which take acceleration and such into account.
