Have you ever noticed that the quality of your playing becomes worse when the height of the organ bench isn't right? That sitting at the convenient height actually helps to make fewer mistakes?
This is especially true about pedal playing because the height of the bench influences how much tension in your leg muscles has to be.
If you adjust the bench so that your feet just touch the pedals without depressing them, you can relax your legs which in turn makes your foot movements quite efficient.
If you sit on the bench that is too low, you have to always tense your leg and even abdominal muscles so that you won't make any accidental depressions of the pedals.
Put some wooden blocks under the bench, if the bench is too low. Sit on the edge of the bench if the bench is too high. In some cases you can even put wooden blocks under organ console to lower the bench height.
Consider yourself lucky, if your organ bench is adjustable.